This update brings some fixes for VP9.
https://chromium.googlesource.com/webm/libvpx/+/v1.4.0

Also, it is ABI incompatible but the only known user of libvpx
is gst1-plugins-good, which is already compatile:
https://bugzilla.gnome.org/show_bug.cgi?id=739476
gst1-plugins-good has released bumped in order to rebuild.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>

libvpx excepts gcc to be used as linker. However, it respects
what is defined in LD. The problem is that LD is defined by
OpenWRT as *-ld.

Forcing the LD env for configure and make solves the problem.
Also, the patch that modified ld call to match what *-ld provides
is not needed anymore.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>

libvpx provides VP8/VP9 Codec SDK, "a high quality,
royalty free, open source codec deployed on millions
of computers and devices worldwide."

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>