[NETFILTER]: silence a warning in ebtables

net/bridge/netfilter/ebtables.c: In function 'ebt_dev_check':
net/bridge/netfilter/ebtables.c:89: warning: initialization discards qualifiers from pointer target type

So make the char* a const char * and the warning is gone.

Signed-off-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>