drivers/block/sata_sil3114.c: Fix GCC 4.6 build warning

drivers/block/sata_sil3114.c: Fix GCC 4.6 build warning

Fix:

sata_sil3114.c: In function 'scan_sata':
sata_sil3114.c:793:7: warning: array subscript is above array bounds [-Warray-bounds]
sata_sil3114.c:794:7: warning: array subscript is above array bounds [-Warray-bounds]
sata_sil3114.c:795:39: warning: array subscript is above array bounds [-Warray-bounds]
sata_sil3114.c:795:7: warning: array subscript is above array bounds [-Warray-bounds]
sata_sil3114.c:797:7: warning: array subscript is above array bounds [-Warray-bounds]
sata_sil3114.c:800:7: warning: array subscript is above array bounds [-Warray-bounds]
sata_sil3114.c:801:7: warning: array subscript is above array bounds [-Warray-bounds]
sata_sil3114.c:802:39: warning: array subscript is above array bounds [-Warray-bounds]
sata_sil3114.c:802:7: warning: array subscript is above array bounds [-Warray-bounds]
sata_sil3114.c:804:7: warning: array subscript is above array bounds [-Warray-bounds]

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>