bmap-tools: switch to main branch

* master branch was removed upstream:
  downloads/git2/github.com.intel.bmap-tools $ git remote prune origin
  Pruning origin
  URL: https://github.com/intel/bmap-tools


   * [pruned] refs/heads/master
   * [pruned] refs/pull/73/merge

* downloads/git2/github.com.intel.bmap-tools $ git branch -a --contains c0673962a8ec1624b5189dc1d24f33fe4f06785a
  main
  release-3.0

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
(cherry picked from commit 369fee18)
Signed-off-by: Steve Sakoman <steve@sakoman.com>