Revert "games/dxx-rebirth: Broken on aarch64"

This reverts commit 7cb3fdd4.

I just build-tested this port on 14.0-RELEASE / aarch64.

games/dxx-rebirth/Makefile

@@ -13,8 +13,6 @@ LICENSE_FILE_GPLv3=	${WRKSRC}/GPL-3.txt
 LICENSE_FILE_PARALLAX=	${WRKSRC}/COPYING.txt
 LICENSE_PERMS_PARALLAX=	dist-mirror pkg-mirror auto-accept
 
-BROKEN_aarch64=	clang crashes, see https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=276700
-
 BUILD_DEPENDS=	as:devel/binutils
 LIB_DEPENDS=	libphysfs.so:devel/physfs \
 		libpng.so:graphics/png