armv8/fsl-layerscape: Remove reference to gdata

The global_data pointer (gd) has been set earlier in crt0_64.S.
So there's no need to assign it again. Remove gdata since it is going
away in U-Boot.

Signed-off-by: Gong Qianyu <Qianyu.Gong@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>

arch/arm/cpu/armv8/fsl-layerscape/spl.c

@@ -44,8 +44,6 @@ u32 spl_boot_mode(void)
 #ifdef CONFIG_SPL_BUILD
 void board_init_f(ulong dummy)
 {
-	/* Set global data pointer */
-	gd = &gdata;
 	/* Clear global data */
 	memset((void *)gd, 0, sizeof(gd_t));
 #if defined(CONFIG_LS2080A) || defined(CONFIG_LS2085A)