buildroot: Update to c7510292dcc2158808ae39eaf51b640f52b4f287

Jeremy Kerr (1):
      package/petitboot: Update to 2e05b1dd0490ce7ecdd15f522e6c700bc6522062

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Merge pull request #34 from jk-ozlabs/master

buildroot: Update to c7510292dcc2158808ae39eaf51b640f52b4f287