MIPS: ralink: add memory definition for RT2880

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

Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/5181/
diff --git a/arch/mips/include/asm/mach-ralink/rt288x.h b/arch/mips/include/asm/mach-ralink/rt288x.h
index ad8b42d..03ad716 100644
--- a/arch/mips/include/asm/mach-ralink/rt288x.h
+++ b/arch/mips/include/asm/mach-ralink/rt288x.h
@@ -46,4 +46,8 @@
 
 #define CLKCFG_SRAM_CS_N_WDT		BIT(9)
 
+#define RT2880_SDRAM_BASE		0x08000000
+#define RT2880_MEM_SIZE_MIN		2
+#define RT2880_MEM_SIZE_MAX		128
+
 #endif