SystemInformation: Fix compilation on HP-UX 11.11 hppa
SystemInformation: Fix compilation on HP-UX 11.11 hppa

Some older versions of HP-UX do not define CPU_IA64_ARCHREV_0, but
CPU_HP_INTEL_EM_1_0 resolves to the same constant (in
/usr/include/sys/unistd.h).

Change-Id: I20f9a161ef62277069a5ba0d339ca09d972a9bae

chuckatkins/KWSys,chuckatkins/KWSys,chuckatkins/KWSys,chuckatkins/KWSys