Align global_data to a 16-byte boundary

Some archs like to have larger alignment for their global data. Use 16 bytes
which suits all current archs.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

common/board_f.c

@@ -499,6 +499,7 @@ static int setup_machine(void)
 static int reserve_global_data(void)
 {
 	gd->start_addr_sp -= sizeof(gd_t);
+	gd->start_addr_sp &= ~0xf;
 	gd->new_gd = (gd_t *)map_sysmem(gd->start_addr_sp, sizeof(gd_t));
 	debug("Reserving %zu Bytes for Global Data at: %08lx\n",
 			sizeof(gd_t), gd->start_addr_sp);

include/asm-generic/global_data.h

@@ -99,7 +99,8 @@ typedef struct global_data {
 	int pcidelay_done;
 #endif
 	struct udevice *cur_serial_dev;	/* current serial device */
-	struct arch_global_data arch;	/* architecture-specific data */
+	/* arch-specific data */
+	struct arch_global_data arch __attribute__((aligned(16)));
 } gd_t;
 #endif