Blackfin/ipipe: restore pipeline bits in irqflags

This patch fixes the Blackfin irqflags to make them I-pipe aware anew,
after the introduction of the hard_local_irq_*() API.

Signed-off-by: Philippe Gerum <rpm@xenomai.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>