mtd: remove alauda driver

The driver has very low utility.  Devices in question are limited to
about 400kB/s and the only known user (me) discarded the hardware
several years back.

Signed-off-by: Joern Engel <joern@logfs.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>