perf: arm_pmuv3: Drop unnecessary IS_ENABLED(CONFIG_ARM64) check

perf: arm_pmuv3: Drop unnecessary IS_ENABLED(CONFIG_ARM64) check

The IS_ENABLED(CONFIG_ARM64) check for threshold support is unnecessary.
The purpose is to not enable thresholds on arm32, but if threshold is
non-zero, the check against threshold_max() just above here will have
errored out because threshold_max() is always 0 on arm32.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Acked-by: Mark rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20240626-arm-pmu-3-9-icntr-v2-2-c9784b4f4065@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>