sdio: fix read buffer overflow

Avoid buffer underrun when parsing an invalid CISTPL_VERS_1.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: David Vrabel <david.vrabel@csr.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>