ceph: cast PAGE_SIZE to size_t in ceph_sync_write()

Use min_t(size_t, ...) instead of plain min(), which does strict type
checking, to avoid compile warning on i386.

Cc: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

fs/ceph/file.c

@@ -734,7 +734,7 @@ static ssize_t ceph_sync_write(struct kiocb *iocb, const struct iovec *iov,
 
 		left = len;
 		for (n = 0; n < num_pages; n++) {
-			size_t plen = min(left, PAGE_SIZE);
+			size_t plen = min_t(size_t, left, PAGE_SIZE);
 			ret = iov_iter_copy_from_user(pages[n], &i, 0, plen);
 			if (ret != plen) {
 				ret = -EFAULT;