ARM: rmobile: Set environment variable containing CPU type

Set environment variable 'platform' containing the CPU type.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index eb6ce29..13ba774 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -784,6 +784,7 @@
 	imply CMD_DM
 	imply FAT_WRITE
 	imply SYS_THUMB_BUILD
+	imply ARCH_MISC_INIT if DISPLAY_CPUINFO
 
 config TARGET_S32V234EVB
 	bool "Support s32v234evb"