When no yamon command line is passed to the kernel, preserve the default
compiled in command line.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/au1000/common/prom.c b/arch/mips/au1000/common/prom.c
index 22e5a85..9c171af 100644
--- a/arch/mips/au1000/common/prom.c
+++ b/arch/mips/au1000/common/prom.c
@@ -75,7 +75,8 @@
 	}
 	if (cp != &(arcs_cmdline[0])) /* get rid of trailing space */
 		--cp;
-	*cp = '\0';
+	if (prom_argc > 1)
+		*cp = '\0';
 
 }