move iov_iter.c from mm/ to lib/

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/lib/Makefile b/lib/Makefile
index 87eb3bf..58f74d2 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -24,7 +24,7 @@
 
 obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
 	 bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \
-	 gcd.o lcm.o list_sort.o uuid.o flex_array.o clz_ctz.o \
+	 gcd.o lcm.o list_sort.o uuid.o flex_array.o iov_iter.o clz_ctz.o \
 	 bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o \
 	 percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o
 obj-y += string_helpers.o