[POWERPC] PMU: Remove dead code

Some code in via-pmu.c is never compiled because of "compile options"
within the file.  Remove the code completely.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>