Blackfin: fix anomaly 283 handling with exact hardware error

The exact hardware error handling code was added before the workaround
for anomaly 283 which caused the anomaly to be triggered in some cases
(an infinite core stall).  So re-order the code to avoid this.

Reported-by: Andrew Rook <andrew.rook@speakerbus.co.uk>
Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>