NFS: Move the pnfs read code into pnfs.c

...and ensure that we recoalese to take into account differences in
block sizes when falling back to read through the MDS.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/objlayout/objio_osd.c b/fs/nfs/objlayout/objio_osd.c
index 70272d5..add6289 100644
--- a/fs/nfs/objlayout/objio_osd.c
+++ b/fs/nfs/objlayout/objio_osd.c
@@ -1007,7 +1007,7 @@
 static const struct nfs_pageio_ops objio_pg_read_ops = {
 	.pg_init = pnfs_generic_pg_init_read,
 	.pg_test = objio_pg_test,
-	.pg_doio = nfs_generic_pg_readpages,
+	.pg_doio = pnfs_generic_pg_readpages,
 };
 
 static const struct nfs_pageio_ops objio_pg_write_ops = {