Make soong config vars available to genrule_bob
Make soong config vars available to genrule_bob

With this we can reference config vars from cmd and args of ninja rules,
limiting usage of hardcoded paths defined in soong.

Change-Id: I8a11fcda672eb12454ff3f645c57a83580c7c43b
Signed-off-by: Michal Przeplata <e7e66087ea2b6f4d3eb01c4545d71a74d74ace14@arm.com>

ARM-software/bob-build,ARM-software/bob-build,ARM-software/bob-build,ARM-software/bob-build,ARM-software/bob-build