bnx2x: Support of PF driver of a VF release request

The 'release' request is the opposite of the 'acquire' request.
At release, all the resources allocated to the VF are reclaimed.
The release flow applies the close flow if applicable.
Note that there are actually two types of release:
1. The VF has been removed, and so issued a 'release' request
over the VF <-> PF Channel.
2. The PF is going down and so has to release all of it's VFs.

Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>