enic: fix an endian bug in enic_probe()

"num_vfs" is a u32 but we only use the high 16 bits and the low 16bits
are left as zero.  That isn't a problem for little endian systems but it
will break on big endian ones.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>