libpayload: disable EHCI & XHCI in defconfig-mips

drivers/usb/xhci.c and drivers/usb/ehci.c both require arch/barrier.h.

barrier.h is present for x86, arm, and arm64, but not for mips. This
is generating a build error after enabling USB by default on libpayload.

I believe that this slipped through the buiders due to them not getting
cleaned fully.  It was caught in the coverity scan and when setting up
a new build server.

Change-Id: Idd89409a048009c087ce2a787d96a1efd089157f
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/14391
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
1 file changed