s390/zcrypt: add multi domain support

Currently the ap infrastructure only supports one domain at a time.
This feature extends the generic cryptographic device driver to
support multiple cryptographic domains simultaneously.

There are now card and queue devices on the AP bus with independent
card and queue drivers. The new /sys layout is as follows:

/sys/bus/ap
    devices
        <xx>.<yyyy> -> ../../../devices/ap/card<xx>/<xx>.<yyyy>
        ...
        card<xx> -> ../../../devices/ap/card<xx>
        ...
    drivers
        <drv>card
            card<xx> -> ../../../../devices/ap/card<xx>
        <drv>queue
            <xx>.<yyyy> -> ../../../../devices/ap/card<xx>/<xx>.<yyyy>
            ...

/sys/devices/ap
    card<xx>
        <xx>.<yyyy>
            driver -> ../../../../bus/ap/drivers/<zzz>queue
            ...
        driver -> ../../../bus/ap/drivers/<drv>card
        ...

The two digit <xx> field is the card number, the four digit <yyyy>
field is the queue number and <drv> is the name of the device driver,
e.g. "cex4".

For compatability /sys/bus/ap/card<xx> for the old layout has to exist,
including the attributes that used to reside there.

With additional contributions from Harald Freudenberger and
Martin Schwidefsky.

Signed-off-by: Ingo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>