avr32: fix linking

This patch fixes following error:

---8<---
avr32-linux-ld: --gc-sections and -r may not be used together
--->8---

Since 8aba9dceebb14144e07d19593111ee3a999c37fc all avr32 boards are broken due
to linking error as seen above.

Signed-off-by: Andreas Bießmann <biessmann@corscience.de>
6 files changed