riscv: dts: starfive: Remove PMIC interrupt info for Visionfive 2 board

Interrupt line number of the AXP15060 PMIC is not a necessary part of
its device tree. Originally the binding required one, so the dts patch
added an invalid interrupt that the driver ignored (0) as the interrupt
line of the PMIC is not actually connected on this platform. This went
unnoticed during review as it would have been a valid interrupt for a
GPIO controller, but it is not for the PLIC. The PLIC, on this platform
at least, silently ignores the enablement of interrupt 0. Bo Gan is
running a modified version of OpenSBI that faults if writes are done to
reserved fields, so their kernel runs into problems.

Delete the invalid interrupt from the device tree.

Cc: stable@vger.kernel.org
Reported-by: Bo Gan <ganboing@gmail.com>
Link: https://lore.kernel.org/all/c8b6e960-2459-130f-e4e4-7c9c2ebaa6d3@gmail.com/


Signed-off-by: Shengyu Qu <wiagn233@outlook.com>
Fixes: 23783415 ("riscv: dts: starfive: Enable axp15060 pmic for cpufreq")
[conor: rewrite the commit message to add more detail]
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>