fs/9p: fix typo in comparison logic for cache mode

There appears to be a typo in the comparison statement for the logic
which sets a file's cache mode based on mount flags.

Cc: stable@vger.kernel.org
Fixes: 1543b4c ("fs/9p: remove writeback fid and fix per-file modes")
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>

Author: ericvh

fs/9p/fid.h

@@ -57,7 +57,7 @@ static inline void v9fs_fid_add_modes(struct p9_fid *fid, int s_flags,
 	   (s_flags & V9FS_DIRECT_IO) || (f_flags & O_DIRECT)) {
 		fid->mode |= P9L_DIRECT; /* no read or write cache */
 	} else if ((!(s_cache & CACHE_WRITEBACK)) ||
-				(f_flags & O_DSYNC) | (s_flags & V9FS_SYNC)) {
+				(f_flags & O_DSYNC) || (s_flags & V9FS_SYNC)) {
 		fid->mode |= P9L_NOWRITECACHE;
 	}
 }