xtensa process.c must #include <linux/fs.h>

Another fallout from the removal of #include <linux/fs.h> from mm.h
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/xtensa/kernel/process.c

@@ -30,6 +30,7 @@
 #include <linux/init_task.h>
 #include <linux/module.h>
 #include <linux/mqueue.h>
+#include <linux/fs.h>
 
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>