devtool: ide-sdk find bitbake-setup init-build-env

devtool: ide-sdk find bitbake-setup init-build-env

With poky the oe-init-build-env script from the top level directory of
the layer with the higher priority is used to setup the build
environment.
This does no longer work with bitbake-setup. The directory layout
changed and the script is now called init-build-env. Skip the old
implementation if $TOPDIR/init-build-env exists and use it instead.

Signed-off-by: Adrian Freihofer <adrian.freihofer@siemens.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>