arm: Move tbl to arch_global_data

Move this field into arch_global_data and tidy up.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/cpu/arm926ejs/mx27/timer.c b/arch/arm/cpu/arm926ejs/mx27/timer.c
index a5dd684..06e3086 100644
--- a/arch/arm/cpu/arm926ejs/mx27/timer.c
+++ b/arch/arm/cpu/arm926ejs/mx27/timer.c
@@ -45,7 +45,7 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#define timestamp	(gd->tbl)
+#define timestamp	(gd->arch.tbl)
 #define lastinc		(gd->lastinc)
 
 /*