drm/radeon/kms: add a new gem_wait ioctl with read/write flags

The new DRM_RADEON_GEM_WAIT ioctl combines GEM_WAIT_IDLE and GEM_BUSY (there
is a NO_WAIT flag to get the latter) with USAGE_READ and USAGE_WRITE flags
to take advantage of the new ttm_bo_wait changes.

Also bump the DRM version.

Signed-off-by: Marek Olšák <maraeo@gmail.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>