habanalabs: enable F/W events after init done

Only after the initialization of the device is done, the driver is
ready to receive events from the F/W. The driver can't handle events
before that because of races so it will ignore events. In case of
a fatal event, the driver won't know about it and the device will be
operational although it shouldn't be.

Same logic should be applied after hard-reset.

Signed-off-by: Oded Gabbay <ogabbay@kernel.org>