perf: apple_m1: Don't disable counter in m1_pmu_enable_event()

perf: apple_m1: Don't disable counter in m1_pmu_enable_event()

Currently m1_pmu_enable_event() starts by disabling the event counter
it has been asked to enable. This should not be necessary as the
counter (and the PMU as a whole) should not be active when
m1_pmu_enable_event() is called.

Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250218-arm-brbe-v19-v20-6-4e9922fc2e8e@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>