adwaita-icon-theme: add a patch to speed up the do_install() task

adwaita-icon-theme: add a patch to speed up the do_install() task

Goes down to 40 seconds from over 4 minutes :)

Note that there is no control over the amount of shell jobs; on my machine
this is not a problem, but if it's a problem on less capable hardware,
we can add some kind of limiter.

Signed-off-by: Alexander Kanavin <alexander.kanavin@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>