qemu: remove ref to now non-existent TARGET_arm64

It was removed in base system commit 88468f7e ("armvirt: merge arm64 as
subtarget 64") in 2017

No change in packaged content

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

utils/qemu/Makefile

@@ -29,7 +29,7 @@ include $(INCLUDE_DIR)/uclibc++.mk
 include $(INCLUDE_DIR)/nls.mk
 include $(INCLUDE_DIR)/package.mk
 
-QEMU_DEPS_IN_GUEST := @(TARGET_x86_64||TARGET_armvirt||TARGET_arm64||TARGET_malta)
+QEMU_DEPS_IN_GUEST := @(TARGET_x86_64||TARGET_armvirt||TARGET_malta)
 QEMU_DEPS_IN_HOST := @(TARGET_x86_64||TARGET_sunxi)
 QEMU_DEPS_IN_HOST += $(CXX_DEPENDS)
 QEMU_DEPS_IN_HOST += $(ICONV_DEPENDS)