Zephyr: drivers: flash: Recent change in spi_nor.c does not let have multiple flash devs on a board.

[gon1332]

Describe the bug
I have a board that has the usual ST's internal flash, and an external SPI NOR one. I want to utilize both flashes in the context of an application. The https://github.com/zephyrproject-rtos/zephyr/commit/7d428bb0a8d35e1198068dff14e47853240f3ee5 introduced the CONFIG_FLASH_SIZE which is also produced for the internal flashes in generated header.

On my local copy, I've overcome this by renaming it to CONFIG_SPI_NOR_SIZE and resolved my issues.

To Reproduce
I've observed it when my memcheck program could not access all the sectors of the external (significantly bigger) SPI NOR flash.

Expected behavior
I expect to have the ability to include an external SPI NOR flash along with the internal.

Additional context
If the used workaround is OK, then ping me to make a fix of it.

[pabigot]

IMO The right fix is to complete moving the SPI drivers to device tree, and specify flash size and other properties in the DTS node. I know @galak has been moving that direction; so had I specifically for spi-nor but now I'm waiting for the dust to settle. We also need to get the jedec,spi-nor compatible yaml in place, and figure out whether we need so many spi nor driver implementations.

[rgundi]

@pabigot and @findlayfeng have done some changes around this which has already been committed to the main tree. @gon1332 Can you please check if your requirements are addressed now?