mtd: nand: omap: ecc.correct: omap_elm_correct_data: rename ambiguous variable 'eccsize' and 'ecc_vector_size'

renaming following variables as they cause confusion due to resemblence to
another similar field in 'struct nand_ecc_ctrl' (nand_chip->ecc.size).
renaming: ecc_vector_size --> ecc->bytes	(info->nand.ecc.bytes)
renaming: eccsize         --> actual_eccbytes	(info->nand.ecc.bytes - 1) for BCH4 and BCH8
Tested-by: Stefan Roese <sr@denx.de>
Signed-off-by: Pekon Gupta <pekon@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>