Since d9a9cdfb07 <linux/sysfs.h> is using
ENOSYS without including <linux/errno.h> if CONFIG_SYSFS is disabled.
Fixed by including <linux/errno.h>.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>