Removing meta-mingw from bblayers.conf.
Removing meta-mingw from bblayers.conf.

The meta-mingw layer adds support for SDK cross-compiling
on Windows. This requirement has been dropped.

Signed-off-by: Charlie Johnston <b1dee96d22a970fd24786261fc8c6eb1012b2c10@ni.com>

ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt