doc/release-notes: Add waffle-next.txt
doc/release-notes: Add waffle-next.txt

This will allow us to build up the release notes for the
next release.

A second reason for wanting to add this is to make sure that
GL is replaced with OpenGL in the release notes.

Signed-off-by: Jordan Justen <a79006884ba9cf5f4f7fcbb92a15b208780d8c97@intel.com>
Reviewed-by: Chad Versace <a557f7f75bf28dc19ac99107f5cc7cd6b3fbdb1a@linux.intel.com>

maurossi/waffle,yinquan529/waffle-gl-waffle,waffle-gl/waffle,yinquan529/waffle-gl-waffle,evelikov/waffle,yinquan529/waffle-gl-waffle,waffle-gl/waffle,janesma/waffle,fjhenigman/waffle,waffle-gl/waffle,chadversary/waffle,dcbaker/waffle,janesma/waffle,fjhenigman/waffle,fjhenigman/waffle,evelikov/waffle,maurossi/waffle,dcbaker/waffle,janesma/waffle,chadversary/waffle,evelikov/waffle,maurossi/waffle,dcbaker/waffle,waffle-gl/waffle,chadversary/waffle