Apply fixes in ena-com

• Change ena-com BIT macro to work on unsigned value. To make the shifting operations safer, they should be working on unsigned values.

• Fix a mutex not owned ASSERT panic in ENA control path. A thread calling cv_broadcast()/cv_signal() must hold the mutex used for cv_wait(). Fix the ENA control path code that has this problem.

Submitted by: Krishna Yenduri <kyenduri@brkt.com>
Reviewed by: Michal Krawczyk <mk@semihalf.com>
Tested by: Michal Krawczyk <mk@semihalf.com>