drm/amd/display: Drop struct crc_region and reuse struct rect

[Why]
reuse struct rect rather than adding a new struct.

[How]
- Userspace keeps inputting x_start, y_start, x_end, y_end
- We translate data to x, y, width, height in code flow to store
- translate back to x_start, y_start, x_end, y_end before programming HW

Tested-by: Mark Broadworth <mark.broadworth@amd.com>
Reviewed-by: Wayne Lin <Wayne.Lin@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alan Liu <HaoPing.Liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>