qlge: Fix sparse endian warning in ql_hw_csum_setup().

Changed u16 to __sum16 usage.

Warnings:
drivers/net/qlge/qlge_main.c:1897:9: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:1897:9:    expected unsigned short [usertype] *check
drivers/net/qlge/qlge_main.c:1897:9:    got restricted unsigned short *<noident>
drivers/net/qlge/qlge_main.c:1903:9: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:1903:9:    expected unsigned short [usertype] *check
drivers/net/qlge/qlge_main.c:1903:9:    got restricted unsigned short *<noident>
drivers/net/qlge/qlge_main.c:1909:9: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:1909:9:    expected unsigned short [unsigned] [short] [usertype] <noident>

Signed-off-by: Ron Mercer <ron.mercer@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>