omap2: Fix console serial port number for n8x0

With the recent changes omap serial ports match the physical
numbering like they should. Fix the kernel CMDLINE accordingly
so console works.
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/configs/n8x0_defconfig

@@ -304,7 +304,7 @@ CONFIG_ALIGNMENT_TRAP=y
 CONFIG_ZBOOT_ROM_TEXT=0x10C08000
 CONFIG_ZBOOT_ROM_BSS=0x10200000
 # CONFIG_ZBOOT_ROM is not set
-CONFIG_CMDLINE="root=1f03 rootfstype=jffs2 console=ttyS0,115200n8"
+CONFIG_CMDLINE="root=1f03 rootfstype=jffs2 console=ttyS2,115200n8"
 # CONFIG_XIP_KERNEL is not set
 # CONFIG_KEXEC is not set