openpic: fix sense and priority bits

openpic: fix sense and priority bits

Previously, the sense and priority bits were masked off when writing
to IVPR, and all interrupts were treated as edge-triggered (despite
the existence of code for handling level-triggered interrupts).

Polarity is implemented only as storage.  We don't simulate the
bad effects that you'd get on real hardware if you set this incorrectly,
but at least the guest sees the right thing when it reads back the register.

Sense now controls level/edge on FSL external interrupts (and all
interrupts on non-FSL MPIC).  FSL internal interrupts do not have a sense
bit (reads as zero), but are level.  FSL timers and IPIs do not have
sense or polarity bits (read as zero), and are edge-triggered.  To
accommodate FSL internal interrupts, QEMU's internal notion of whether an
interrupt is level-triggered is separated from the IVPR bit.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>