genirq/timings: Fix error return code in irq_timings_test_irqs()

genirq/timings: Fix error return code in irq_timings_test_irqs()

[ Upstream commit 290fdc4b7ef14e33d0e30058042b0e9bfd02b89b ]

Return a negative error code from the error handling case instead of 0, as
done elsewhere in this function.

Fixes: f52da98d900e ("genirq/timings: Add selftest for irqs circular buffer")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210811093333.2376-1-thunder.leizhen@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>