drm/amdgpu/dce8: Use cursor_set2 hook for enabling / disabling the HW cursor

drm/amdgpu/dce8: Use cursor_set2 hook for enabling / disabling the HW cursor

The cursor_set2 hook provides the cursor hotspot position within the
cursor image. When the hotspot position changes, we can adjust the cursor
position such that the hotspot doesn't move on the screen. This prevents
the cursor from appearing to intermittently jump around on the screen
when the position of the hotspot within the cursor image changes.

Port of radeon commits:
78b1a6010b46a69bcd47b723a80f92693f26d17b
3feba08d79c32777a845c3c8a4ab93092bdf6f19

Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>