Blackfin: fix up PATA resource handling in bf537-stamp

Make sure the addresses declared match reality, and make the PATA IRQ code
optional.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>