drm/amd/display: Fix dcn10 cursor set position hang

Calling dcn10_cursor_set_position() before dcn10_cursor_set_attributes()
with invalid (0-value) attributes can cause the ASIC to hang. This fix
checks that address.quadpart is non-zero within set_position before calling
set_attributes.

Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>