Adjust ENA driver to the new ena-com

Adjust ENA driver to the new ena-com

Recent HAL change preparing to support ENAv2 required minor driver
modifications.

The ena_com_sq_empty_space() is not available in this ena-com, so it had
to be replaced with ena_com_free_desc().

Moreover, the ena_com_admin_init() is no longer using 3rd argument
indicating if the spin lock should be initialized, so it was removed.

Submitted by:  Michal Krawczyk <mk@semihalf.com>
Obtained from: Semihalf
Sponsored by:  Amazon, Inc.