tools: build: Use HOSTLDFLAGS with fixdep

The final link of fixdep uses LDFLAGS but not the existing HOSTLDFLAGS.
Fix this.

Signed-off-by: Laura Abbott <labbott@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>