mtd: maps: remove obsolete ipaq-flash driver

This driver seems to be obsolete and broken for a long time.
It depends on CONFIG_IPAQ_HANDHELD that simply doesn't exists
anywhere in kernel. Also, it seems that none of machines it
claims to support have any use of it:
 SA11xx-based iPAQs (h3100/h3600) use sa1100-flash
 iPAQ h5000 uses physmap-flash
 Jornada 720 uses sa1100-flash
 Jornada 560 and iPAQ h1910 are not in mainline

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>