habanalabs: Include linux/bitfield.h only in habanalabs.h

Include linux/bitfield.h only in habanalabs.h, instead of in each and
every file that needs it, as habanalabs.h is already included by all.

Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>