NFS4: Cleanup FATTR4_WORD0_FS_LOCATIONS after decoding success

Commit 1ca843a "nfs: Fix GETATTR bitmap verification" has check
the bitmap after decoding success, but decode_attr_fs_locations forgets
cleanup the FATTR4_WORD0_FS_LOCATIONS bits.

decode_getfattr_attrs always return -EIO when meeting FS_LOCATIONS now.

ls: cannot access /mnt/referal: Input/output error
ls: cannot access /mnt/replicas: Input/output error
total 32
drwxr-xr-x. 7 root root 8192 Nov 16 20:36 pnfs
??????????? ? ?    ?       ?            ? referal
??????????? ? ?    ?       ?            ? replicas

v2: clear the bit earlier

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4xdr.c

@@ -3615,6 +3615,7 @@ static int decode_attr_fs_locations(struct xdr_stream *xdr, uint32_t *bitmap, st
 	status = 0;
 	if (unlikely(!(bitmap[0] & FATTR4_WORD0_FS_LOCATIONS)))
 		goto out;
+	bitmap[0] &= ~FATTR4_WORD0_FS_LOCATIONS;
 	status = -EIO;
 	/* Ignore borken servers that return unrequested attrs */
 	if (unlikely(res == NULL))