mm/shmem.c: remove an ifdef

Create a CONFIG_MMU=y stub for ramfs_nommu_expand_for_mapping() in the
usual fashion.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/ramfs.h b/include/linux/ramfs.h
index 5bf5500..69e37c2 100644
--- a/include/linux/ramfs.h
+++ b/include/linux/ramfs.h
@@ -6,7 +6,13 @@
 extern struct dentry *ramfs_mount(struct file_system_type *fs_type,
 	 int flags, const char *dev_name, void *data);
 
-#ifndef CONFIG_MMU
+#ifdef CONFIG_MMU
+static inline int
+ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
+{
+	return 0;
+}
+#else
 extern int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize);
 extern unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
 						   unsigned long addr,