Makefile: Move include directories to INC_DIRS variable

I really hate the Atmel copy+paste style makefile where every include path
is specified three times, rather than using variables.

Change-Id: I39dd880ced341aaea54e30e8b670dbaea445aa8b
1 file changed
tree: e33efe7dcb15cdf852afe0234ae81f468845f16e
  1. ccid/
  2. contrib/
  3. sysmoOCTSIM/