nfs: fix PNFS_FLEXFILE_LAYOUT Kconfig default

stable inclusion
from linux-4.19.184
commit 208142a84d57b11f8da9cbf710a54a205277eea7

--------------------------------

[ Upstream commit a0590473 ]

This follows what was done in 8c2fabc6.
With the default being m, it's impossible to build the module into the
kernel.
Signed-off-by: NTimo Rothenpieler <timo@rothenpieler.org>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

fs/nfs/Kconfig

@@ -127,7 +127,7 @@ config PNFS_BLOCK
 config PNFS_FLEXFILE_LAYOUT
 	tristate
 	depends on NFS_V4_1 && NFS_V3
-	default m
+	default NFS_V4
 
 config NFS_V4_1_IMPLEMENTATION_ID_DOMAIN
 	string "NFSv4.1 Implementation ID Domain"