Since meson switch and commit feabc71d ("configure: do not include
dependency flags in QEMU_CFLAGS and LIBS"), LIBS is unused.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210114125605.1227742-2-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>