ixgbe(4): Fix enabling/disabling and reconfiguration of queues

• Wrong order of casting and bit shift caused that enabling and disabling queues didn't work properly for queues number larger than 32. Use literals with right suffix instead.

• TX ring tail address was not updated during reinitiailzation of TX structures. It could block sending traffic.

• Also remove unused variables 'eims' and 'active_queues'.

Submitted by: Krzysztof Galazka <krzysztof.galazka@intel.com>
Reviewed by: erj@
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D20826

(cherry picked from commit 2dc2d580354e95491a033fa9e21c8ef0cbd9bc42)