pl061: implement input interrupt logic

pl061: implement input interrupt logic

This patch adds the missing input interrupt logic to the pl061 GPIO device. To
keep the floating output pins to stay high, the old state variable had to be
split into two separate ones for input and output - which brings the vmstate
version to 3.

Edge level interrupts and I/O were tested under Linux 3.14. Level interrupt
handling hasn't been tested.

Signed-off-by: Colin Leitner <colin.leitner@googlemail.com>
Message-id: 54024FD2.9080204@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>