omap3: Use a define for reboot reason offset

This introduces a define for the offset to the reboot reason, rather than
hardcoding it.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/include/asm/arch-omap3/omap.h b/arch/arm/include/asm/arch-omap3/omap.h
index 4044b8d..bc0e02a 100644
--- a/arch/arm/include/asm/arch-omap3/omap.h
+++ b/arch/arm/include/asm/arch-omap3/omap.h
@@ -249,6 +249,8 @@
 /* ABB tranxdone mask */
 #define OMAP_ABB_MPU_TXDONE_MASK	(0x1 << 26)
 
+#define OMAP_REBOOT_REASON_OFFSET	0x04
+
 /* Boot parameters */
 #ifndef __ASSEMBLY__
 struct omap_boot_parameters {