powerpc/perf_counter: Add support for POWER6

This adds the back-end for the PMU on the POWER6 processor.
Fortunately, the event selection hardware is somewhat simpler on
POWER6 than on other POWER family processors, so the constraints
fit into only 32 bits.

Signed-off-by: Paul Mackerras <paulus@samba.org>
3 files changed