[MTD] Don't oops when the RedBoot partition table is empty

This fixes a regression with the RedBoot parsing code introduced by
commit 0b47d654089c5ce3f2ea26a4485db9bcead1e515

Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
1 file changed