Revert "MIPS: perf: ath79: Fix perfcount IRQ assignment"

This reverts commit ca864881 which is
commit a1e8783db8e0d58891681bc1e6d9ada66eae8e20 upstream.

Petr writes:
	Karl has reported to me today, that he's experiencing weird
	reboot hang on his devices with 4.9.180 kernel and that he has
	bisected it down to my backported patch.

	I would like to kindly ask you for removal of this patch.  This
	patch should be reverted from all stable kernels up to 5.1,
	because perf counters were not broken on those kernels, and this
	patch won't work on the ath79 legacy IRQ code anyway, it needs
	new irqchip driver which was enabled on ath79 with commit
	51fa4f8912c0 ("MIPS: ath79: drop legacy IRQ code").

Reported-by: Petr Štetiar <ynezz@true.cz>
Cc: Kevin 'ldir' Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
Cc: John Crispin <john@phrozen.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>