The Micron mt25qu02g supports both x2 and x4 transactions. Add the
SPI_NOR_DUAL_READ flag to its spi_nor_ids[] table entry.
Tested on Pensando SoC hardware with a cadence quadspi controller
via drivers/spi/spi-cadence-quadspi.c, in x2 mode at 50MHz.
- random data write, erase, read - verified erase operations
- random data write, read/compare - verified write/read operations