Fix the ifdef clause that was being used in the opposite way, setting
a wrong value of the carry bit.
This is also correcting 2 memory accesses that were mistakenly referring
to r0 while they were supposed to mean the immediate value 0.
[BZ #22142]
* stdio-common/tst-printf.c (fp_test): Add tests for DBL_MAX and
-DBL_MAX.
(do_test): Likewise.
* stdio-common/tst-printf.sh: Likewise.
* sysdeps/powerpc/powerpc64/power7/add_n.S: Invert the initial
ifdef clause in order to set the carry bit right. Replace r0 by
0 without changing the behavior.
179dcdb7af