common: Move hang() to the same header as panic()

At present panic() is in the vsprintf.h header file. That does not seem
like an obvious choice for hang(), even though it relates to panic(). So
let's put hang() in its own header.

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: Migrate a few more files]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/compulab/cl-som-imx7/spl.c b/board/compulab/cl-som-imx7/spl.c
index 6833608..360c4df 100644
--- a/board/compulab/cl-som-imx7/spl.c
+++ b/board/compulab/cl-som-imx7/spl.c
@@ -8,6 +8,7 @@
  */
 
 #include <common.h>
+#include <hang.h>
 #include <init.h>
 #include <spl.h>
 #include <fsl_esdhc_imx.h>
diff --git a/board/compulab/cm_fx6/spl.c b/board/compulab/cm_fx6/spl.c
index 1ddf424..592d741 100644
--- a/board/compulab/cm_fx6/spl.c
+++ b/board/compulab/cm_fx6/spl.c
@@ -9,6 +9,7 @@
 
 #include <common.h>
 #include <clock_legacy.h>
+#include <hang.h>
 #include <init.h>
 #include <spl.h>
 #include <asm/io.h>
diff --git a/board/compulab/cm_t43/spl.c b/board/compulab/cm_t43/spl.c
index fdab9c3..016c63a 100644
--- a/board/compulab/cm_t43/spl.c
+++ b/board/compulab/cm_t43/spl.c
@@ -4,6 +4,7 @@
  */
 
 #include <common.h>
+#include <hang.h>
 #include <init.h>
 #include <spl.h>
 #include <i2c.h>