mtd: rawnand: omap_elm: remove redundant variable 'errors'

The variable 'errors' is being used to sum the number of errors
but it is never used afterwards. This can be considered a
redundant set of operations and can be removed.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20211221181340.524639-1-colin.i.king@gmail.com