misc: add Qualcomm GENI SE QUP device driver

This change adds a Qualcomm GENI SE QUP device driver as a wrapper for
actually enabled and used serial devices found on a board.

At the moment the driver is pretty simple, its intention is to populate
childred devices and provide I/O mem read interface to them as clients,
this is needed for GENI UART driver to set up a proper clock divider
and provide the actually asked baud rate.

Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>