mtd: spinand: macronix: Add Quad support for serial NAND flash

Adding FLAG "SPINAND_HAS_QE_BIT" for Quad mode support on Macronix
Serial Flash.
Validated via normal(default) and QUAD mode by read, erase, read back,
on Xilinx Zynq PicoZed FPGA board which included Macronix
SPI Host(drivers/spi/spi-mxic.c).

Signed-off-by: Jaime Liao <jaimeliao@mxic.com.tw>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/1628472472-32008-1-git-send-email-jaimeliao@mxic.com.tw