ARM: global_data: make set_gd() work for armv5 and armv6

The Thumb instruction `ldr` is able to move high registers only from
armv7. For armv5 and armv6 we have to use `mov`.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/include/asm/global_data.h

@@ -122,8 +122,10 @@ static inline void set_gd(volatile gd_t *gd_ptr)
 {
 #ifdef CONFIG_ARM64
 	__asm__ volatile("ldr x18, %0\n" : : "m"(gd_ptr));
-#else
+#elif __ARM_ARCH >= 7
 	__asm__ volatile("ldr r9, %0\n" : : "m"(gd_ptr));
+#else
+	__asm__ volatile("mov r9, %0\n" : : "r"(gd_ptr));
 #endif
 }