drm/amdgpu/display: Update kdoc for 'optc35_set_odm_combine'

The parameters segment_width and last_segment_width are used to control
the configuration of the Output Plane Processor (OPP), specifically the
width of each segment that the display is divided into and the width of
the last segment

Fixes the below with gcc W=1:
drivers/gpu/drm/amd/amdgpu/../display/dc/optc/dcn35/dcn35_optc.c:59: warning: Function parameter or struct member 'segment_width' not described in 'optc35_set_odm_combine'
drivers/gpu/drm/amd/amdgpu/../display/dc/optc/dcn35/dcn35_optc.c:59: warning: Function parameter or struct member 'last_segment_width' not described in 'optc35_set_odm_combine'
drivers/gpu/drm/amd/amdgpu/../display/dc/optc/dcn35/dcn35_optc.c:59: warning: Excess function parameter 'timing' description in 'optc35_set_odm_combine'

Cc: Tom Chung <chiahsuan.chung@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Roman Li <roman.li@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>