global: Move remaining CONFIG_SYS_SDRAM_* to CFG_SYS_SDRAM_*

The rest of the unmigrated CONFIG symbols in the CONFIG_SYS_SDRAM
namespace do not easily transition to Kconfig. In many cases they likely
should come from the device tree instead. Move these out of CONFIG
namespace and in to CFG namespace.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/README b/README
index 5ab042a..b095937 100644
--- a/README
+++ b/README
@@ -1441,7 +1441,7 @@
 		the RAM base is not zero, or RAM is divided into banks,
 		this variable needs to be recalcuated to get the address.
 
-- CONFIG_SYS_SDRAM_BASE:
+- CFG_SYS_SDRAM_BASE:
 		Physical start address of SDRAM. _Must_ be 0 here.
 
 - CONFIG_SYS_FLASH_BASE: