mtd: nandsim: remove autoincrement code

The NAND layer always has NAND_NO_AUTOINCR set, so we will never utilize the
AUTOINCR code in nandsim. We will be removing the NAND_NO_AUTOINCR option soon,
and so kill this code as well.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>