network: vlan-aware bridge: fix pvid when trunks is defined

network: vlan-aware bridge: fix pvid when trunks is defined

Currently, when a trunks is defined, the vlan tag is not used
for pvid with vlan-aware bridge. (It's ok with ovs switch)

example:

net0: e1000=BA:90:68:B8:CF:F5,bridge=vmbr1,tag=2,trunks=2-11

before
------
tap100i0	 2-11

after
-----
tap100i0	 2 PVID Egress Untagged
	 3-11

No regression for other configurations:

net0: e1000=BA:90:68:B8:CF:F5,bridge=vmbr1

before
------
tap100i0	 1 PVID Egress Untagged
	 2-4094

after
-----
tap100i0	 1 PVID Egress Untagged
	 2-4094

net0: e1000=BA:90:68:B8:CF:F5,bridge=vmbr1,tag=2

before
------
tap100i0	 2 PVID Egress Untagged

after
-----
tap100i0	 2 PVID Egress Untagged

net0: e1000=BA:90:68:B8:CF:F5,bridge=vmbr1,trunks=2-11

before
------
tap100i0	 1 PVID Egress Untagged
	 2-11

after
-----
tap100i0	 1 PVID Egress Untagged
	 2-11

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>