mtd: spi-nor: fsl-quadspi: add support for ls1021a

LS1021a also support Freescale Quad SPI controller.
Add fsl-quadspi support for ls1021a chip and make SPI_FSL_QUADSPI
selectable for LS1021A SOC hardwares.

Signed-off-by: Yuan Yao <yao.yuan@nxp.com>
Acked-by: Han xu <han.xu@freescale.com>
Acked-by: Han xu <han.xu@nxp.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>