post: Move CONFIG_SYS_POST to CFG_SYS_POST

Migrate the rest of the CONFIG_SYS_POST macros over to CFG_SYS_POST
namespace.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
index 369a8e3..9a380d7 100644
--- a/drivers/serial/serial.c
+++ b/drivers/serial/serial.c
@@ -458,7 +458,7 @@
 		dev->putc(*s++);
 }
 
-#if CFG_POST & CONFIG_SYS_POST_UART
+#if CFG_POST & CFG_SYS_POST_UART
 static const int bauds[] = CFG_SYS_BAUDRATE_TABLE;
 
 /**