ksz884x: fix Endian

ETH_P_IP is host Endian, skb->protocol is big Endian, when
compare them, Using htons on skb->protocol is wrong.

And fix two code style issues: indentation and remove
unnecessary parentheses.

CC: Tristram Ha <Tristram.Ha@micrel.com>
CC: Ben Hutchings <bhutchings@solarflare.com>
CC: Joe Perches <joe@perches.com>
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>