MIPS: ralink: add memory definition for RT305x

Populate struct soc_info with the data that describes our RAM window.

As memory detection fails on RT5350 we read the amount of available memory
from the system controller.

Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/5180/
diff --git a/arch/mips/include/asm/mach-ralink/rt305x.h b/arch/mips/include/asm/mach-ralink/rt305x.h
index 80cda8a..069bf37 100644
--- a/arch/mips/include/asm/mach-ralink/rt305x.h
+++ b/arch/mips/include/asm/mach-ralink/rt305x.h
@@ -157,4 +157,10 @@
 #define RT3352_RSTCTRL_UDEV		BIT(25)
 #define RT3352_SYSCFG1_USB0_HOST_MODE	BIT(10)
 
+#define RT305X_SDRAM_BASE		0x00000000
+#define RT305X_MEM_SIZE_MIN		2
+#define RT305X_MEM_SIZE_MAX		64
+#define RT3352_MEM_SIZE_MIN		2
+#define RT3352_MEM_SIZE_MAX		256
+
 #endif