multilib.eclass: Upgrade to upstream version

Upgrade multilib.eclass to latest upstream version.

BUG=chromium:916320
TEST=CQ

Change-Id: I724cf55a95f899d27a02bee6135cc31b5e3921e2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/2276455
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
Tested-by: Manoj Gupta <manojgupta@chromium.org>
1 file changed