mtd: nand: pxa3xx: Fix SEQIN column address set

This commit adds support page programming with a non-zero "column"
address setting. This is important to support OOB writing, through
command sequences such as:

  cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize, ofs);
  write_buf(mtd, oob_buf, 6);
  cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Tested-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>