hw/ssi/xilinx_spips: Convert lqspi_read() to read_with_attrs

hw/ssi/xilinx_spips: Convert lqspi_read() to read_with_attrs

In the next commit we will implement the write_with_attrs()
handler. To avoid using different APIs, convert the read()
handler first.

Reviewed-by: Francisco Iglesias <frasse.iglesias@gmail.com>
Tested-by: Francisco Iglesias <frasse.iglesias@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit 5937bd50d3841b6ab2592c1ff4233448762a8483)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>