Blackfin: boards: use proper irq flags with isp1362-hcd

With the recent kernel update the isp1362-hcd driver evaluates the
IORESOURCE_IRQ resource flags and requests the irq with the given
polarity/edge settings.  However the ISP1362 config requires low
level/edge interrupts.  Most of the Blackfin boards use some random
flag or no flag at all.  Make all boards use a know good flag
IORESOURCE_IRQ_LOWEDGE.

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