Make the XHCI driver compile on ARM again. The Panther Point
specific shutdown handler is certainly _not_ necessary there.
Change-Id: I470afd4d82d101902b119b3ead4381e2b36a94b0
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: http://review.coreboot.org/10091
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>