thunderbolt, efi: Fix Kconfig dependencies

Fix this EFI build failure on certain (rand)configs:

  drivers/firmware/efi/apple-properties.c:149:9: error: implicit declaration of function ???efi_get_device_by_path??? [-Werror=implicit-function-declaration]

which is due to:

  warning: (THUNDERBOLT) selects APPLE_PROPERTIES which has unmet direct dependencies (EFI && EFI_STUB && X86)
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Pedro Vilaça <reverser@put.as>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Pierre Moreau <pierre.morrow@free.fr> [MacBookPro11,3]
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20161114151033.GA10141@wunner.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

drivers/thunderbolt/Kconfig

 menuconfig THUNDERBOLT
 	tristate "Thunderbolt support for Apple devices"
 	depends on PCI
-	select APPLE_PROPERTIES
+	select APPLE_PROPERTIES if EFI_STUB
 	select CRC32
 	help
 	  Cactus Ridge Thunderbolt Controller driver