drm/xe: Print registers spread in 2 u32 as u64

drm/xe: Print registers spread in 2 u32 as u64

This makes easier to use those registers when copying its values to
calculator also makes easier for tools to parse it.

To avoids padding holes in xe_hw_engine_snapshot the u64 variables
were moved to the top of xe_hw_engine_snapshot.reg.

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Maarten Lankhorst <dev@lankhorst.se>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240123204454.246788-6-jose.souza@intel.com