platform/chrome: cros_ec_typec: Add a dependency on USB_ROLE_SWITCH

As reported by the kernel test robot the cros_ec_typec driver fails to
build if the USB_ROLE_SWITCH is not selected, to fix that, add a
dependency on that symbol. This fixes the following build error:

   drivers/platform/chrome/cros_ec_typec.c:133: undefined reference to `usb_role_switch_put'
   ld: drivers/platform/chrome/cros_ec_typec.o: in function `cros_typec_get_switch_handles':
   drivers/platform/chrome/cros_ec_typec.c:108: undefined reference to `fwnode_usb_role_switch_get'
   ld: drivers/platform/chrome/cros_ec_typec.c:117: undefined reference to `usb_role_switch_put'

Fixes: 7e7def1 ("platform/chrome: cros_ec_typec: Add USB mux control")
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Prashant Malani <pmalani@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

drivers/platform/chrome/Kconfig

@@ -218,6 +218,7 @@ config CROS_EC_TYPEC
 	tristate "ChromeOS EC Type-C Connector Control"
 	depends on MFD_CROS_EC_DEV && TYPEC
 	depends on CROS_USBPD_NOTIFY
+	depends on USB_ROLE_SWITCH
 	default MFD_CROS_EC_DEV
 	help
 	  If you say Y here, you get support for accessing Type C connector