datapath-windows: Increase the maximum size of port name.

datapath-windows: Increase the maximum size of port name.

In userspace, port name sizes are restricted to IFNAMSIZ which is
defined to IF_NAME_SIZE in:
C:\Program Files (x86)\Windows Kits\8.1\Include\shared\netioapi.h

In the kernel, since IFNAMSIZ was not available, we previously defined a
value of 16 for the kernel. This is restrictive for Openstack
integration where we use UUID as the name.

In this patch, we make the kernel code also use the same value as the
userspace.

Also updated is the OVS.psm1 powershell script which now allows friendly
names to be upto 48 bytes.

Signed-off-by: Nithin Raju <nithin@vmware.com>
Acked-by: Eitan Eliahu <eliahue@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>