i2c: designware-baytrail: another fixup for proper Kconfig dependencies

IOSF_MBI is tristate. Baytrail driver isn't.
Reported-by: NRandy Dunlap <rdunlap@infradead.org>
Acked-by: NDavid E. Box <david.e.box@linux.intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/Kconfig

@@ -477,7 +477,7 @@ config I2C_DESIGNWARE_PCI
 
 config I2C_DESIGNWARE_BAYTRAIL
 	bool "Intel Baytrail I2C semaphore support"
-	depends on I2C_DESIGNWARE_PLATFORM && IOSF_MBI && ACPI
+	depends on I2C_DESIGNWARE_PLATFORM && IOSF_MBI=y && ACPI
 	help
 	  This driver enables managed host access to the PMIC I2C bus on select
 	  Intel BayTrail platforms using the X-Powers AXP288 PMIC. It allows