The avr backend supports __builtin_return_address only for the current 
stack frame. The test expects it to work for caller frames as well and 
therefore fails for avr.

Add avr to the list of targets already excluded with dg-skip-if.

gcc/testsuite/ChangeLog:

2016-09-06  Senthil Kumar Selvaraj  <senthil_kumar.selvaraj@atmel.com>

	* gcc.dg/Wno-frame-address.c: Skip for avr-*-*.

From-SVN: r240005