src/console: Sanitize headers and IS_ENABLED usage

Alphabetise headers and remove any #if CONFIG_ guards around them.
Use #if IS_ENABLED(CONFIG_FOO) over #if CONFIG_FOO where applicable.

Change-Id: I2a616bcfb8470a1fa21c9e26271e81cca835272a
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/6057
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

src/console/vtxprintf.c

@@ -4,9 +4,9 @@
  *  Copyright (C) 1991, 1992  Linus Torvalds
  */
 
-#include <string.h>
 #include <console/console.h>
 #include <console/vtxprintf.h>
+#include <string.h>
 
 #define call_tx(x) tx_byte(x, data)