sxgbe: fix duplicate #include headers

The commit 1edb9ca6 ("net: sxgbe: add basic framework for
Samsung 10Gb ethernet driver") added support for Samsung 10Gb
ethernet driver(sxgbe) with a minor issue of including linux/io.h
header twice in sxgbe_dma.c file. Fix the duplicate #include by
deleting the top one so that all the rest good #include headers
would be preserved in the alphabetical order.

Signed-off-by: Jean Sacren <sakiwit@gmail.com>
Cc: Byungho An <bh74.an@samsung.com>
Cc: Girish K S <ks.giri@samsung.com>
Cc: Siva Reddy Kallam <siva.kallam@samsung.com>
Cc: Vipul Pandya <vipul.pandya@samsung.com>
Acked-by: Byungho An <bh74.an@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>