mtd: spi-nor: intel-spi: Avoid crossing 4K address boundary on read/write

It was observed that reads crossing 4K address boundary are failing.

This limitation is mentioned in Intel documents:

Intel(R) 9 Series Chipset Family Platform Controller Hub (PCH) Datasheet:

"5.26.3 Flash Access
Program Register Access:
* Program Register Accesses are not allowed to cross a 4 KB boundary..."

Enhanced Serial Peripheral Interface (eSPI)
Interface Base Specification (for Client and Server Platforms):

"5.1.4 Address
For other memory transactions, the address may start or end at any byte
boundary. However, the address and payload length combination must not
cross the naturally aligned address boundary of the corresponding Maximum
Payload Size. It must not cross a 4 KB address boundary."

Avoid this by splitting an operation crossing the boundary into two
operations.

Fixes: 8afda8b2

 ("spi-nor: Add support for Intel SPI serial flash controller")
Cc: stable@vger.kernel.org
Reported-by: Romain Porte <romain.porte@nokia.com>
Tested-by: Pascal Fabreges <pascal.fabreges@nokia.com>
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>