arm: perf: xscale: condense event maps

Now that we have macros for declaring fully invalid event maps, put them
to work for the XScale PMU event maps. While this necessitates repeating
common indices, we no longer need to refer to *_UNSUPPORTED events at
all, and it makes it possible for the even maps to fit on a single page
on a reasonably sized monitor.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>