drm: Delete the DRM_DEBUG_KMS in drm_mode_cursor_ioctl

We can get the corresponding info by adding the boot option of "drm.debug=
0x07". But On some boxes it will print the following message many times in
course of moving mouse. In such case the useful DRM debug info will be flushed.
   >[drm:drm_mode_cursor_ioctl],

Avoid using the DRM_DEBUG_KMS in drm_mode_cursor_ioctl.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>