[CIFS] Fix compiler warnings

Fix some compiler warnings noticed on x64 by me and ppc64 by Shaggy

Signed-off-by: Steve French (sfrench@us.ibm.com)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index a9c791e..cd421c7 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -331,7 +331,7 @@
 	return sb->s_fs_info;
 }
 
-static inline const char CIFS_DIR_SEP(const struct cifs_sb_info *cifs_sb)
+static inline char CIFS_DIR_SEP(const struct cifs_sb_info *cifs_sb)
 {
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)
 		return '/';