mpc83xx: Rename CONFIG_SYS_DDR_CONFIG and cleanup DDR csbnds code

Rename CONFIG_SYS_DDR_CONFIG to include which CS it is configuring
Cleanup the setting of the csnbds to respect the setting of
CONFIG_SYS_DDR_SDRAM_BASE
Use __ilog2 instead of writing the code to compute it
Disable unused CS configs
Ensure ddrlaw.bar is configured

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Cc: Joe Hershberger <joe.hershberger@gmail.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
diff --git a/board/freescale/mpc8313erdb/sdram.c b/board/freescale/mpc8313erdb/sdram.c
index 7aede13..a9a2ba4 100644
--- a/board/freescale/mpc8313erdb/sdram.c
+++ b/board/freescale/mpc8313erdb/sdram.c
@@ -74,8 +74,14 @@
 	 */
 	__udelay(50000);
 
-	im->ddr.csbnds[0].csbnds = (msize - 1) >> 24;
-	im->ddr.cs_config[0] = CONFIG_SYS_DDR_CONFIG;
+#if ((CONFIG_SYS_DDR_SDRAM_BASE & 0x00FFFFFF) != 0)
+#warning Chip select bounds is only configurable in 16MB increments
+#endif
+	im->ddr.csbnds[0].csbnds =
+		((CONFIG_SYS_DDR_SDRAM_BASE >> CSBNDS_SA_SHIFT) & CSBNDS_SA) |
+		(((CONFIG_SYS_DDR_SDRAM_BASE + msize - 1) >> CSBNDS_EA_SHIFT) &
+			CSBNDS_EA);
+	im->ddr.cs_config[0] = CONFIG_SYS_DDR_CS0_CONFIG;
 
 	/* Currently we use only one CS, so disable the other bank. */
 	im->ddr.cs_config[1] = 0;