[Bug testsuite/78740] test case powerpc/pr78691-ppc.c fails starting with its introduction in r243335

[wschmidt at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78740

--- Comment #2 from Bill Schmidt <wschmidt at gcc dot gnu.org> ---
I think the target restriction

/* { dg-do compile { target { powerpc*-*-* && ilp32 } } } */

is probably sufficient to fix this.  I can test that in a bit.