ibmvnic: Insert header on VLAN tagged received frame

This patch addresses a modification in the PAPR+ specification which now
defines a previously reserved value for vNIC capabilities. It indicates
whether the system firmware performs a VLAN header stripping on all VLAN
tagged received frames, in case it does, the behavior expected is for
the ibmvnic driver to be responsible for inserting the VLAN header.

Reported-by: Manvanthara B. Puttashankar <mputtash@in.ibm.com>
Signed-off-by: Murilo Fossa Vicentini <muvic@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>