package/gcc: fix ICE on xtensa, 5.x and 6.x, PR target/78603

Zero overhead loop optimization pass may incorrectly put start of the
loop between a call and its CALL_ARG_LOCATION note, resulting in the
following build error:

  ../src/pjlib-test/thread.c: In function 'thread_test':
  ../src/pjlib-test/thread.c:328:1: internal compiler error: in
    dwarf2out_var_location, at dwarf2out.c:21846

Fixes:
  http://autobuild.buildroot.net/results/d919e1276ce1d39b4b3eb09937927d5959cd69a3/



Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>