mtd: spi-nor: Allow post_sfdp hook to return errors

Multi die flashes like s25hl02gt need to determine the page_size at
run-time by querying a configuration register for each die. Since the
number of dice is determined in an optional SFDP table, SCCR MC, the
page size configuration must be done in the post_sfdp hook. Allow
post_sfdp to return errors, as reading the configuration register might
return errors.

Link: https://lore.kernel.org/r/924ab710f128448ec62537cfbb377336e390043c.1680849425.git.Takahiro.Kuwano@infineon.com


Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>