spi: airoha: add support of dual/quad wires spi modes to exec_op() handler

spi: airoha: add support of dual/quad wires spi modes to exec_op() handler

Booting without this patch and disabled dirmap support results in

[    2.980719] spi-nand spi0.0: Micron SPI NAND was found.
[    2.986040] spi-nand spi0.0: 256 MiB, block size: 128 KiB, page size: 2048, OOB size: 128
[    2.994709] 2 fixed-partitions partitions found on MTD device spi0.0
[    3.001075] Creating 2 MTD partitions on "spi0.0":
[    3.005862] 0x000000000000-0x000000020000 : "bl2"
[    3.011272] 0x000000020000-0x000010000000 : "ubi"
...
[    6.195594] ubi0: attaching mtd1
[   13.338398] ubi0: scanning is finished
[   13.342188] ubi0 error: ubi_read_volume_table: the layout volume was not found
[   13.349784] ubi0 error: ubi_attach_mtd_dev: failed to attach mtd1, error -22
[   13.356897] UBI error: cannot attach mtd1

If dirmap is disabled or not supported in the spi driver, the dirmap requests
will be executed via exec_op() handler. Thus, if the hardware supports
dual/quad spi modes, then corresponding requests will be sent to exec_op()
handler. Current driver does not support such requests, so error is arrised.
As result the flash can't be read/write.

This patch adds support of dual and quad wires spi modes to exec_op() handler.

Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>