[Bug target/94622] testsuite/gcc.dg/atomic/c11-atomic-exec-1.c fails on powerpc64le with -mpcrel

[acsawdey at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94622

--- Comment #2 from acsawdey at gcc dot gnu.org ---
Solution is going to be to always use plq if prefixed, which makes sense anyway
for little endian because it avoids the ugly doubleword swap.