sbc8560: properly set cs0_bnds for 512MB

The sbc8560 board ships with 512MB of memory installed,
but the current cs0_bnds is hard coded for 256MB.  Set the
value based on CFG_SDRAM_SIZE.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/board/sbc8560/sbc8560.c b/board/sbc8560/sbc8560.c
index 2946ca1..3b6b541 100644
--- a/board/sbc8560/sbc8560.c
+++ b/board/sbc8560/sbc8560.c
@@ -421,7 +421,11 @@
   #ifndef CFG_RAMBOOT
 	volatile ccsr_ddr_t *ddr= (void *)(CFG_MPC85xx_DDR_ADDR);
 
+#if (CFG_SDRAM_SIZE == 512)
+	ddr->cs0_bnds		= 0x0000000f;
+#else
 	ddr->cs0_bnds		= 0x00000007;
+#endif
 	ddr->cs1_bnds		= 0x0010001f;
 	ddr->cs2_bnds		= 0x00000000;
 	ddr->cs3_bnds		= 0x00000000;