mtd: edb7312: correctly pass MTD name to parsers

cmdline partitions parser expects MTD name at mtd->name, instead of
origin, while edb7312 passes MTDID as origin. Fix that.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>