drivers/perf: arm_pmu: Fix leak in error path

In case of a IRQ type mismatch in of_pmu_irq_cfg() the
device node for interrupt affinity isn't freed. So fix this
issue by calling of_node_put().

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Fixes: fa8ad788

 ("arm: perf: factor arm_pmu core out to drivers")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>