lib: make iovec obj instead of lib

Fix build error io vmw_vmci.ko when CONFIG_VMWARE_VMCI=m by chaning
iovec.o from lib-y to obj-y.

  ERROR: "memcpy_toiovec" [drivers/misc/vmw_vmci/vmw_vmci.ko] undefined!
  ERROR: "memcpy_fromiovec" [drivers/misc/vmw_vmci/vmw_vmci.ko] undefined!

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/Makefile

@@ -9,7 +9,7 @@ endif
 
 lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 rbtree.o radix-tree.o dump_stack.o timerqueue.o\
-	 idr.o int_sqrt.o extable.o iovec.o \
+	 idr.o int_sqrt.o extable.o \
 	 sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \
 	 proportions.o flex_proportions.o prio_heap.o ratelimit.o show_mem.o \
 	 is_single_threaded.o plist.o decompress.o kobject_uevent.o \
@@ -23,7 +23,7 @@ lib-y	+= kobject.o klist.o
 
 obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
 	 bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \
-	 gcd.o lcm.o list_sort.o uuid.o flex_array.o \
+	 gcd.o lcm.o list_sort.o uuid.o flex_array.o iovec.o \
 	 bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o
 obj-y += string_helpers.o
 obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o