clk: zynqmp: Fix kernel-doc format

clk: zynqmp: Fix kernel-doc format

Align structure and function names with definitions.

Issues are reported by kernel-doc script as:
drivers/clk/zynqmp/clk-gate-zynqmp.c:24: warning: expecting prototype for
struct clk_gate. Prototype was for struct zynqmp_clk_gate instead
drivers/clk/zynqmp/clk-gate-zynqmp.c:75: warning: expecting prototype for
zynqmp_clk_gate_is_enable(). Prototype was for zynqmp_clk_gate_is_enabled()
instead

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/26526e144296373b2c75e75865dd023158f9bfc7.1629718424.git.michal.simek@xilinx.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>