ARM: mach-shmobile: early console support using earlyprintk

Add support for early console to the SH-Mobile boards.

Simply perform an early platform probe for "earlyprintk"
to trigger the early serial console code in sh-sci.c.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/arm/configs/g3evm_defconfig b/arch/arm/configs/g3evm_defconfig
index d323ff7..3c19031 100644
--- a/arch/arm/configs/g3evm_defconfig
+++ b/arch/arm/configs/g3evm_defconfig
@@ -317,7 +317,7 @@
 #
 CONFIG_ZBOOT_ROM_TEXT=0x0
 CONFIG_ZBOOT_ROM_BSS=0x0
-CONFIG_CMDLINE="console=ttySC1,115200"
+CONFIG_CMDLINE="console=ttySC1,115200 earlyprintk=sh-sci.1,115200"
 # CONFIG_XIP_KERNEL is not set
 CONFIG_KEXEC=y
 CONFIG_ATAGS_PROC=y