drm/amd/display: Add kdoc entry for 'program_isharp_1dlut' in 'dpp401_dscl_program_is...

drm/amd/display: Add kdoc entry for 'program_isharp_1dlut' in 'dpp401_dscl_program_isharp'

Added a descriptor for the 'program_isharp_1dlut' parameter, which is a
flag used to determine whether to program the isharp 1D LUT.

Fixes the below with gcc W=1:
drivers/gpu/drm/amd/amdgpu/../display/dc/dpp/dcn401/dcn401_dpp_dscl.c:963: warning: Function parameter or struct member 'program_isharp_1dlut' not described in 'dpp401_dscl_program_isharp'

Cc: Tom Chung <chiahsuan.chung@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Roman Li <roman.li@amd.com>
Cc: Alex Hung <alex.hung@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Hamza Mahfooz <hamza.mahfooz@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>