libavb: Only print basename of file in avb_debug() and friends.

In some setups where libavb is used, the macro __FILE__ evaluates to a
really long strings such as


meaning that debug output is cluttered to the point that it's not
useful. Unfortunately there's no __FILENAME__ macro in C so instead
figure out the basename at runtime.

Bug: None
Test: New unit tests and unit tests pass.
Test: Tested on various boot loaders.
Change-Id: Icb7d407bc0960d50ac069d3426a48531775dcf89
3 files changed