bsd-user: update aarch64-bsd-user.mak gdb XML list

Fixes unreachable code assert in qemu:smoke / bsd-user-smoke test.

Upstream commit: 591e848aca

Pull-Request: https://github.com/qemu-bsd-user/qemu-bsd-user/pull/61
Signed-off-by: Siva Mahadevan <me@svmhdvn.name>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Warner Losh <imp@bsdimp.com>

configs/targets/aarch64-bsd-user.mak

@@ -1,4 +1,4 @@
 TARGET_ARCH=aarch64
 TARGET_BASE_ARCH=arm
-TARGET_XML_FILES= gdb-xml/aarch64-core.xml gdb-xml/aarch64-fpu.xml gdb-xml/aarch64-pauth.xml gdb-xml/aarch64-sme2.xml
+TARGET_XML_FILES= gdb-xml/aarch64-core.xml gdb-xml/aarch64-fpu.xml gdb-xml/aarch64-pauth.xml gdb-xml/aarch64-mte.xml gdb-xml/aarch64-sme2.xml
 TARGET_LONG_BITS=64