Compare right field when printing summary

The check

  if (coverage->calls && coverage->calls == 0)

will always be false (as reported by -Wlogical-op) and broken.  I
don't think there is a test suite for function summaries so this was
not caught earlier.

The logic is a bit awkward and could've been flipped to avoid checking
calls_suppressed twice.  When it was written I wanted to minimize
patch and preserve the "natural" order, since the suppression pragma
is an opt-in, in a way.

	PR gcov-profile/127408

gcc/ChangeLog:

	* gcov.cc (function_summary): Check calls_suppressed, not calls.