xtensa: re-wire umount syscall to sys_oldumount

Userspace actually passes single parameter (path name) to the umount
syscall, so new umount just fails. Fix it by requesting old umount
syscall implementation and re-wiring umount to it.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: xtfpga: add generic KC705 board config

This config enables most important features, NFS or FLASH rootfs and
minimal debug.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: xtfpga: add lx200 SMP DTS and defconfig

This config allows running SMP-enabled bitstream on LX200 board.
NFS or FLASH rootfs, minimal debug, up to 4 cores.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>