drm/amd/display: Provide function name for 'optc32_enable_crtc()'

Fixes the following W=1 kernel build warning(s):

drivers/gpu/drm/amd/amdgpu/../display/dc/dcn32/dcn32_optc.c:109: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* Enable CRTC

Cc: Rodrigo Siqueira <[e-mail]>
Cc: Aurabindo Pillai <[e-mail]>
Cc: Harry Wentland <[e-mail]>
Signed-off-by: Srinivasan Shanmugam <[e-mail]>
Reviewed-by: Rodrigo Siqueira <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_optc.c

···
 			OTG_H_TIMING_DIV_MODE_MANUAL, manual_mode ? 1 : 0);
 }
 /**
- * Enable CRTC
- * Enable CRTC - call ASIC Control Object to enable Timing generator.
+ * optc32_enable_crtc() - Enable CRTC - call ASIC Control Object to enable Timing generator.
+ *
+ * @optc: timing_generator instance.
+ *
+ * Return: If CRTC is enabled, return true.
  */
 static bool optc32_enable_crtc(struct timing_generator *optc)
 {