x86/irq: Move IOAPIC misrouted and PIC/APIC error counts into irq_stats

x86/irq: Move IOAPIC misrouted and PIC/APIC error counts into irq_stats

The special treatment of these counts is just adding extra code for no real
value. The irq_stats mechanism allows to suppress output of counters, which
should never happen by default and provides a mechanism to enable them for
the rare case that they occur.

Move the IOAPIC misrouted and the PIC/APIC error counts into irq_stats,
mark them suppressed by default and update the sites which increment them.

This changes the output format of 'ERR' and 'MIS' in case there are events
to the regular per CPU display format and otherwise suppresses them
completely.

As a side effect this removes the arch_cpu_stat() mechanism from proc/stat
which was only there to account for the error interrupts on x86 and missed
to take the misrouted ones into account.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Radu Rendec <radu@rendec.net>
Link: https://patch.msgid.link/20260517194931.361942103@kernel.org