ppc/ide/macio: Add missing registers

ppc/ide/macio: Add missing registers

The timing register exists on all variants of MacIO IDE, we just
store and return its value.

The interrupts register only exists on KeyLargo but it doesn't
hurt to have it. The lack of this register causes MacOS X to
hangs under some circumstances.

Both are 32-bit only. The HW might support smaller access sizes
but no known OS uses them.

Because the core IDE subsystem doesn't provide us with a way
to query the main (level) interrupt state, nor do we have a way
to know that DBDMA issued a (edge) interrupt, we reflect both
through a private pair of qirq's in order to maintain the
register state.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>