nfsd4: mask out non-access bits in nfs4_access_to_omode

This fixes an unnecessary BUG().

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3dfef06..cf0d2ff 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -440,7 +440,7 @@
 
 static int nfs4_access_to_omode(u32 access)
 {
-	switch (access) {
+	switch (access & NFS4_SHARE_ACCESS_BOTH) {
 	case NFS4_SHARE_ACCESS_READ:
 		return O_RDONLY;
 	case NFS4_SHARE_ACCESS_WRITE: