iwlwifi: fix ICT irq table endianness

The ICT IRQ table is a set of __le32 values, not u32 values,
so when reading it we need to take into account that it has
to be converted to CPU endianness. This was causing a lot of
trouble on my powerpc box where various things would simply
not work for no apparent reason with 5xxx cards, but worked
with 4965 -- which doesn't use the ICT table.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>