xilinx_spips: seperate SPI and QSPI as two classes

xilinx_spips: seperate SPI and QSPI as two classes

Make SPI and QSPI different classes. QSPIPS is setup as a child of SPIPS.
Only QSPI has the LQSPI functionality, so move all that to the child class.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Message-id: 2cdd0cadb5ba77ca02fde5cae627852dc9a64c71.1369117359.git.peter.crosthwaite@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>