arm: mvebu: spl.c: Remove useless gd declaration

ddaa905 ("arm: mvebu: Add DM (driver model) support") removed the
assignment of the gd pointer, but kept the (now superfluous) declaration
of the gd pointer.

Remove this declaration.

Signed-off-by: Reinhard Pfau <pfau@gdsys.de>
Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Stefan Roese <sr@denx.de>

arch/arm/mach-mvebu/spl.c

@@ -13,8 +13,6 @@
 #include <asm/arch/cpu.h>
 #include <asm/arch/soc.h>
 
-DECLARE_GLOBAL_DATA_PTR;
-
 static u32 get_boot_device(void)
 {
 	u32 val;