drivers/spi_nor: allow application control of flash layout page size

The driver historically used the erase block size (64 KiBy) as the page
size.  There are other viable "sector" sizes, and for some applications
this one may be too large.  Allow the application to specify the desired
flash page size.

Signed-off-by: Peter A. Bigot <pab@pabigot.com>
2 files changed