sun4i-drm fixes for 4.9
A few patches to fix our error handling and our panel / bridge calls.
* tag 'sunxi-drm-fixes-for-4.9' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux:
drm/sun4i: Propagate error to the caller
drm/sun4i: Fix error handling
drm/sun4i: rgb: Remove the bridge enable/disable functions
drm/sun4i: rgb: Enable panel after controller