package/luvi: fix build with aarch64_be

Fix the following build failure with aarch64_be raised since the
addition of aarch64_be support to luajit in commit
28e5c2f2bdd147dbb9aefbc040fc618f46ee0663:

luajit: unknown architecture

Fixes: 28e5c2f2bdd147dbb9aefbc040fc618f46ee0663
 - http://autobuild.buildroot.org/results/9b89eff7d90173b8c74b8f676650709cc4418e65

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/luvi/luvi.mk

@@ -22,6 +22,8 @@ else ifeq ($(BR2_arm)$(BR2_armeb),y)
 LUVI_TARGET_ARCH = arm
 else ifeq ($(BR2_aarch64),y)
 LUVI_TARGET_ARCH = arm64
+else ifeq ($(BR2_aarch64_be),y)
+LUVI_TARGET_ARCH = arm64be
 else ifeq ($(BR2_mips),y)
 LUVI_TARGET_ARCH = mips
 else ifeq ($(BR2_mipsel),y)