arm: Disable maintenance interrupt on successful injection

arm: Disable maintenance interrupt on successful injection

We enable the maintenance interrupt when all list registers are in use.
However, there was no disabling of it again. Apparently, it rarely
triggered in the field, otherwise we would have seen a lot of
maintenance interrupt storms, thus locked-up systems.

This introduces another callback to enable or disable the maintenance
interrupt. It is now controlled by irqchip_inject_pending, the function
that is also called when handling a maintenance interrupt.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>