fsi: scom: Don't abort operations for minor errors

The scom driver currently fails out of operations if certain system
errors are flagged in the status register; system checkstop, special
attention, or recoverable error. These errors won't impact the ability
of the scom engine to perform operations, so the driver should continue
under these conditions.
Also, don't do a PIB reset for these conditions, since it won't help.

Fixes: 6b293258

 ("fsi: scom: Major overhaul")
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20190827041249.13381-1-jk@ozlabs.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>