staging: Disable lustre file system for MIPS, SH, and XTENSA

mips allmodconfig fails with

ERROR: "copy_from_user_page" [drivers/staging/lustre/lustre/libcfs/libcfs.ko]
undefined!

which is due to LUSTRE using copy_from_user_page which is not exported by any
architecture. Unfortunately, LUSTRE can only be built as module, so there is no
easy fix.

MIPS, SH, and optionally XTENSA implement copy_from_user_page as unexported
functions. Disable LUSTRE for those.

Cc: Peng Tao <bergwolf@gmail.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/Kconfig

 config LUSTRE_FS
 	tristate "Lustre file system client support"
-	depends on INET && m
+	depends on INET && m && !MIPS && !XTENSA && !SUPERH
 	select LNET
 	select CRYPTO
 	select CRYPTO_CRC32