docs: ioctl-number.rst: add habanalabs driver IOCTL

Habanalabs driver in misc exposes several IOCTLs to userspace. Document the
letter and IOCTLs number range in ioctl-number.rst.

Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20200418174132.10597-1-oded.gabbay@gmail.com


Signed-off-by: Jonathan Corbet <corbet@lwn.net>