ARM: shmobile: alt dts: Drop console= bootargs parameter

Alt is booted from DT, so chosen/stdout-path is
always used, and we can drop the "console=" parameter from chosen/bootargs.

This change has a side-effect of changing the console speed from 38400
to 115200. This is intentional as 115200 is consistently used on
all other shmobile boards.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7794-alt.dts

@@ -20,7 +20,7 @@ aliases {
 	};
 
 	chosen {
-		bootargs = "console=ttySC0,38400 ignore_loglevel rw root=/dev/nfs ip=dhcp";
+		bootargs = "ignore_loglevel rw root=/dev/nfs ip=dhcp";
 		stdout-path = &scif2;
 	};