i2c: designware: Allow build Baytrail semaphore support when IOSF_MBI=m

I believe i2c-designware-baytrail.c doesn't have strict dependency that
Intel SoC IOSF Sideband support must be always built-in in order to be
able to compile support for Intel Baytrail I2C bus sharing HW semaphore.

Redefine build dependencies so that CONFIG_IOSF_MBI=y is required only
when CONFIG_I2C_DESIGNWARE_PLATFORM is built-in.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: David Box <david.e.box@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/Kconfig

@@ -490,7 +490,9 @@ config I2C_DESIGNWARE_PCI
 
 config I2C_DESIGNWARE_BAYTRAIL
 	bool "Intel Baytrail I2C semaphore support"
-	depends on I2C_DESIGNWARE_PLATFORM && IOSF_MBI=y && ACPI
+	depends on ACPI
+	depends on (I2C_DESIGNWARE_PLATFORM=m && IOSF_MBI) || \
+		   (I2C_DESIGNWARE_PLATFORM=y && IOSF_MBI=y)
 	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