simple-bus: remove DECLARE_GLOBAL_DATA_PTR

No global pointer is used in this file.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/core/simple-bus.c b/drivers/core/simple-bus.c
index 14803e3..5acfa5f 100644
--- a/drivers/core/simple-bus.c
+++ b/drivers/core/simple-bus.c
@@ -7,8 +7,6 @@
 #include <common.h>
 #include <dm.h>
 
-DECLARE_GLOBAL_DATA_PTR;
-
 struct simple_bus_plat {
 	u32 base;
 	u32 size;