[gem] Move potentially device-specific ioctls to the intel driver.

This is the create (may want location flags), pread/pwrite/mmap
(performance tuning hints), and set_domain (will 32 bits be enough for
everyone?) ioctls.  Left in the generic set are just flink/open/close.

The 2D driver must be updated for this change, and API but not ABI is broken
for 3D.  The driver version is bumped to mark this.