Fixes the following W=1 kernel build warning:

display/dc/dcn10/dcn10_optc.c:45: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* apply_front_porch_workaround  TODO FPGA still need?
display/dc/dcn10/dcn10_optc.c:136: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * program_timing_generator   used by mode timing set
display/dc/dcn10/dcn10_optc.c:391: warning: Function parameter or member 'optc' not described in 'optc1_set_timing_double_buffer'
display/dc/dcn10/dcn10_optc.c:391: warning: Function parameter or member 'enable' not described in 'optc1_set_timing_double_buffer'
display/dc/dcn10/dcn10_optc.c:404: warning: Function parameter or member 'optc' not described in 'optc1_unblank_crtc'
display/dc/dcn10/dcn10_optc.c:404: warning: expecting prototype for unblank_crtc(). Prototype was for optc1_unblank_crtc() instead
display/dc/dcn10/dcn10_optc.c:427: warning: Function parameter or member 'optc' not described in 'optc1_blank_crtc'
display/dc/dcn10/dcn10_optc.c:427: warning: expecting prototype for blank_crtc(). Prototype was for optc1_blank_crtc() instead
display/dc/dcn10/dcn10_optc.c:496: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Enable CRTC
display/dc/dcn10/dcn10_optc.c:895: warning: Cannot understand  *****************************************************************************
 on line 895 - I thought it was a doc line

Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>