fs: Move many prototypes to pagemap.h

These functions are page cache functionality and don't need to be
declared in fs.h.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>

fs/coda/file.c

@@ -14,6 +14,7 @@
 #include <linux/time.h>
 #include <linux/file.h>
 #include <linux/fs.h>
+#include <linux/pagemap.h>
 #include <linux/stat.h>
 #include <linux/cred.h>
 #include <linux/errno.h>