We have generic place & helpers for storing platform driver data so
there is no reason for using custom priv pointer.

This allows cleaning up struct bcma_sflash from unneeded fields.
Signed-off-by: NRafał Miłecki <rafal@milecki.pl>
Acked-by: NKalle Valo <kvalo@codeaurora.org>
Acked-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>