SoC: mxs-saif: check validity of ids in mxs_saif_probe()

There is a check for validity of one of ids in mxs_saif_probe(),
while array dereferece is made by the other id.

The patch adds the check for the second saif id.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Mark Brown <broonie@kernel.org>