mtd: spinand: Introduce a way to avoid raw access

SkyHigh spinand device has ECC enable bit in configuration register but
it must be always enabled. If ECC is disabled, read and write ops
results in undetermined state. For such devices, a way to avoid raw
access is needed.

Introduce SPINAND_NO_RAW_ACCESS flag to advertise the device does not
support raw access. In such devices, the on-die ECC engine ops returns
error to I/O request in raw mode.

Checking and marking BBM need to be cared as special case, by adding
fallback mechanism that tries read/write OOB with ECC enabled.

Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>