[MTD] [MAPS] physmap: fix wrong free and del_mtd_{partition,device}

commit 176bf2e0 ("physmap: fix leak of
memory returned by parse_mtd_partitions") deals with a memory leak and
frees the pointer array of mtd_partition after the call to
add_mtd_partitions().  the problem is that mtd_table[x]->name still points
to the freed memory.

Aldo physmap_flash_remove() should call del_mtd_partitions() or
del_mtd_device() only once.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Reported-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Tested-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>