bnx2x: VF <-> PF channel 'acquire' at vf probe

Add the 'acquire' request to VF <-> PF channel and use it at
VF probe. In the acquire request the VF driver lists the resources
it would like to have. In the response the PF either ratifies the
request, or denies it and supplies the maximum values supported.
The VF may then attempt another acquire request.
This patch adds the bnx2x_vfpf.c file which contains the
implementation of the VF to PF hardware channel.

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>