regulator: Update protection IRQ helper docs

The documentation of IRQ notification helper had still references to
first RFC implementation which called BUG() while trying to protect the
hardware. Behaviour was improved as calling the BUG() was not a proper
solution. Current implementation attempts to call poweroff if handling
of potentially damaging error notification fails. Update the
documentation to reflect the actual behaviour.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Link: https://lore.kernel.org/r/0c9cc4bcf20c3da66fd5a85c97ee4288e5727538.1637233864.git.matti.vaittinen@fi.rohmeurope.com


Signed-off-by: Mark Brown <broonie@kernel.org>