network/ifup.sh: enable bridged vlan interfaces

network/ifup.sh: enable bridged vlan interfaces

To use vlan for net boot, you need to specify vlan and ip kernel options
for the boot interface. For example,

 vlan=eth1.1:eth1 bootdev=eth1.1
 ip=1.2.3.4:1.2.3.4::255.255.255.0:my-hostname:eth1:none

To use bridge for net boot, you need to specify bridge and ip kernel
option for the boot interface. For example

 bridge=br1:eth1 bootdev=br1
 ip=1.2.3.4:1.2.3.4::255.255.255.0:my-hostname:eth1:none

In my environment, I needs to boot machines from network within
a vlan or on a bridged network.	I found curent dracut release
if-up.sh script in 40network module bypass ip setting for both
bridge and vlan interface.