bnx2x: Add to VF <-> PF channel the release request

VF driver uses this request when removed. The PF driver
reclaims all resources allocated for that VF at this
time.

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>