fix issue reported by 0-Day with randconfig

The commit a68bc0d4
("ASoC: Intel: Atom: auto-detection of Baytrail-CR")
added a dependency on IOSF_MBI. The code used the IS_ENABLED macro
to check for this dependency but this is not enough in case the SST
driver is built-in. This could be fixed with IS_REACHABLE but
Baytrail-CR would not be detected depending on combinations of options

Add dependency in Kconfig to solve this for good
Reported-by: 0 day tester <fengguang.wu@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>