firmware: fix GOOGLE_SMI kconfig dependency warning

Is it meaningful/useful to enable EFI_VARS but not EFI?
That's what GOOGLE_SMI does.  Make it enable EFI also.

Fixes this kconfig dependency warning:

warning: (GOOGLE_SMI) selects EFI_VARS which has unmet direct dependencies (EFI)
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/firmware/google/Kconfig

@@ -13,6 +13,7 @@ menu "Google Firmware Drivers"
 config GOOGLE_SMI
 	tristate "SMI interface for Google platforms"
 	depends on ACPI && DMI
+	select EFI
 	select EFI_VARS
 	help
 	  Say Y here if you want to enable SMI callbacks for Google