Adapt the i.MX23 MCI driver to the v2 i.MX23 patch series
The i.MX23 v2 architecture patch series was sligthly modified to easify
the i.MX28 architecture addition later on. So, we need now an index to
query the SSP clock frequency.
Signed-off-by: Juergen Beisert <jbe@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>