amilo-rfkill: Add dependency on SERIO_I8042

I forgot to add this when changing the driver to use the proper
i8042 functions.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

drivers/platform/x86/Kconfig

@@ -176,6 +176,7 @@ config FUJITSU_TABLET
 config AMILO_RFKILL
 	tristate "Fujitsu-Siemens Amilo rfkill support"
 	depends on RFKILL
+	depends on SERIO_I8042
 	---help---
 	  This is a driver for enabling wifi on some Fujitsu-Siemens Amilo
 	  laptops.