drm/amdgpu: Fix truncations in gfx_v11_0_init_microcode()

drm/amdgpu: Fix truncations in gfx_v11_0_init_microcode()

Reducing the size of ucode_prefix to 25 in the gfx_v11_0_init_microcode
function. This would ensure that the total number of characters being
written into fw_name does not exceed its size of 40.

Fixes the below with gcc W=1:
drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c: In function ‘gfx_v11_0_early_init’:
drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:523:54: warning: ‘_pfp.bin’ directive output may be truncated writing 8 bytes into a region of size between 4 and 33 [-Wformat-truncation=]
  523 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_pfp.bin", ucode_prefix);
      |                                                      ^~~~~~~~
drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:523:9: note: ‘snprintf’ output between 16 and 45 bytes into a destination of size 40
  523 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_pfp.bin", ucode_prefix);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:540:54: warning: ‘_me.bin’ directive output may be truncated writing 7 bytes into a region of size between 4 and 33 [-Wformat-truncation=]
  540 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_me.bin", ucode_prefix);
      |                                                      ^~~~~~~
drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:540:9: note: ‘snprintf’ output between 15 and 44 bytes into a destination of size 40
  540 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_me.bin", ucode_prefix);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:557:70: warning: ‘_rlc.bin’ directive output may be truncated writing 8 bytes into a region of size between 4 and 33 [-Wformat-truncation=]
  557 |                         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_rlc.bin", ucode_prefix);
      |                                                                      ^~~~~~~~
drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:557:25: note: ‘snprintf’ output between 16 and 45 bytes into a destination of size 40
  557 |                         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_rlc.bin", ucode_prefix);
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:569:54: warning: ‘_mec.bin’ directive output may be truncated writing 8 bytes into a region of size between 4 and 33 [-Wformat-truncation=]
  569 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_mec.bin", ucode_prefix);
      |                                                      ^~~~~~~~
drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:569:9: note: ‘snprintf’ output between 16 and 45 bytes into a destination of size 40
  569 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_mec.bin", ucode_prefix);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  CC [M]  drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_clockpowergating.o

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Suggested-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>