treewide: Clean up DECLARE_GLOBAL_DATA_PTR usage

Remove DECLARE_GLOBAL_DATA_PTR from files where gd is not used, and
drop the unnecessary inclusion of asm/global_data.h.

Headers should be included directly by the files that need them,
rather than indirectly via global_data.h.

Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com> #STMicroelectronics boards and STM32MP1 ram test driver
Tested-by: Anshul Dalal <anshuld@ti.com> #TI boards
Acked-by: Yao Zi <me@ziyao.cc> #TH1520
Signed-off-by: Peng Fan <peng.fan@nxp.com>

boot/bootmeth-uclass.c

@@ -19,8 +19,6 @@
 #include <mapmem.h>
 #include <dm/uclass-internal.h>
 
-DECLARE_GLOBAL_DATA_PTR;
-
 int bootmeth_get_state_desc(struct udevice *dev, char *buf, int maxsize)
 {
 	const struct bootmeth_ops *ops = bootmeth_get_ops(dev);

boot/fdt_simplefb.c

@@ -8,14 +8,11 @@
 
 #include <dm.h>
 #include <fdt_support.h>
-#include <asm/global_data.h>
 #include <linux/libfdt.h>
 #include <video.h>
 #include <spl.h>
 #include <bloblist.h>
 
-DECLARE_GLOBAL_DATA_PTR;
-
 static int fdt_simplefb_configure_node(void *blob, int off)
 {
 	int xsize, ysize;

boot/image-sig.c

@@ -5,8 +5,6 @@
 
 #include <log.h>
 #include <malloc.h>
-#include <asm/global_data.h>
-DECLARE_GLOBAL_DATA_PTR;
 #include <image.h>
 #include <relocate.h>
 #include <u-boot/ecdsa.h>

boot/image.c

@@ -24,12 +24,9 @@
 #include <fdt_support.h>
 #endif
 
-#include <asm/global_data.h>
 #include <linux/errno.h>
 #include <asm/io.h>
 
-DECLARE_GLOBAL_DATA_PTR;
-
 /* Set this if we have less than 4 MB of malloc() space */
 #if CONFIG_SYS_MALLOC_LEN < (4096 * 1024)
 #define CONSERVE_MEMORY		true