Correctly read the POWER cycle counter
Correctly read the POWER cycle counter

The upper register can overflow so we need to re-read the upper
register to ensure we we not on a boundary.

GH #1460

randombit/botan,randombit/botan,randombit/botan,webmaster128/botan,randombit/botan,webmaster128/botan,webmaster128/botan,randombit/botan,webmaster128/botan,webmaster128/botan