The VF will send a message to request multicast addresses with the
default VID. In the current code, if the PF has statically assigned a
VLAN to a VF, then the VF will not get the multicast addresses. Fix up
all of the various VLAN messages to use identical checks (since each
check was different). Also use set as a variable, so that it simplifies
our check for whether VLAN matches the pf_vid.

The new logic will allow set of a VLAN if it is zero, automatically
converting to the default VID. Otherwise it will allow setting the PF
VID, or any VLAN if PF has not statically assigned a VLAN. This is
consistent behavior, and allows VF to request either 0 or the
default_vid without silently failing.

Note that we need the check for zero since VFs might not get the default
VID message in time to actually request non-zero VLANs.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>