pseries: Clear TCE and signal state when resetting PAPR VIO devices

pseries: Clear TCE and signal state when resetting PAPR VIO devices

When we reset the system, the reset method for VIO bus devices resets
the state of their request queue (if present) as it should.  However
it was not resetting the state of their TCE table (DMA translation) if
present.  It was also not resetting the state of the per-device signal
mask set with H_VIO_SIGNAL.  This patch corrects both bugs, and also
removes some small code duplication in the reset paths.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>