mtd: rawnand: omap_gpmc: Fix BCH6/16 HW based correction

The BCH detection hardware can generate ECC bytes for multiple
sectors in one go. Use that feature.

correct() only corrects one sector at a time so we need to call it
repeatedly for each sector.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Link: https://lore.kernel.org/all/20221220102203.52398-2-rogerq@kernel.org