drm/amd/display: Align hwss_wait_for_all_blank_complete descriptor with implementation

drm/amd/display: Align hwss_wait_for_all_blank_complete descriptor with implementation

The descriptor for `hwss_wait_for_all_blank_complete` was previously
misaligned with the actual implementation. This commit refines the
descriptor to reflect the implementation of
`hwss_wait_for_all_blank_complete`

Fixes the below with gcc W=1:
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_hw_sequencer.c:991: warning: expecting prototype for hwss_wait_for_blank_complete(). Prototype was for hwss_wait_for_all_blank_complete() instead

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>