KVM: arm64: Always support SW_INCR PMU event

KVM: arm64: Always support SW_INCR PMU event

Support for SW_INCR is unconditional, as KVM traps accesses to
PMSWINC_EL0 and emulates the intended event increment. While it is
expected that ~all PMUv3 implementations already advertise this event,
non-PMUv3 hardware may not.

Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305202641.428114-5-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>