[POWERPC] Remove 'console=' from cmdline on prpmc2800

Specifying 'console=ttyMM0' on the cmdline for the prmpc2800 is no
longer necessary.
Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/boot/dts/prpmc2800.dts

@@ -309,7 +309,7 @@
 	};
 
 	chosen {
-		bootargs = "ip=on console=ttyMM0";
+		bootargs = "ip=on";
 		linux,stdout-path = "/mv64x60@f1000000/mpsc@8000";
 	};
 };