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/board/sipeed/maix/maix.c b/board/sipeed/maix/maix.c
index a218278..79e492f 100644
--- a/board/sipeed/maix/maix.c
+++ b/board/sipeed/maix/maix.c
@@ -11,7 +11,7 @@
 
 phys_size_t get_effective_memsize(void)
 {
-	return CONFIG_SYS_SDRAM_SIZE;
+	return CFG_SYS_SDRAM_SIZE;
 }
 
 static int sram_init(void)