drivers/spi_nor: remove configurability of page/sector/block sizes

The JEDEC API defines the hardware page, sector, and block sizes.
Deprecate the Kconfig settings, remove the `erase-size-block` property,
and add `has-be32k` to indicate that 32K-byte erase is supported.
Rework the driver to use the constants instead of configured values.

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