xen/arm: gic and vgic fixes

xen/arm: gic and vgic fixes

- the last argument of find_next_bit is the maximum number of bits, not
the maximum number of bytes;

- use list_for_each_entry_safe instead of list_for_each_entry in
gic_restore_pending_irqs because we are actually deleting entries in the
loop.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>