RFR(M): 8194814 [ppc, s390] A row of minor fixes and cleanups

[Lindenmaier, Goetz]

Hi,

could I please get a review for this collection of minor fixes
and cleanups in the ppc and s390 platform files?
http://cr.openjdk.java.net/~goetz/wr18/8194814-ppcCleanup/webrev.01/

Thanks,
  Goetz.