mtd: onenand: fix warning (integer used as pointer)
mtd: onenand: fix warning (integer used as pointer)

Fixes this sparse warning:

    CHECK   drivers/mtd/onenand/generic.c
  drivers/mtd/onenand/generic.c:61:62: warning: Using plain integer as NULL pointer

Signed-off-by: Brian Norris <ac73eed4b8a8c9127255a2696c52b2e7503720b8@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs