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