arm64: zynqmp: Change the spi-rx-bus-width property to x1

As per the zc1275 design x1 mode is enabled so changing the
spi-rx-bus-width property to x1.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>