xf86drm: add drmGetDeviceFromDevId
This adds a function to get a drmDevicePtr from a dev_t identifier of a device. This is useful for Wayland that uses these to identify devices over the protocol.
This is done by taking the implementation of drmGetDevice2, and removing the call to fstat to find the dev_t.
Signed-off-by: Scott Anderson scott.anderson@collabora.com Signed-off-by: Simon Ser contact@emersion.fr