mtd: remove the h1910 NAND driver

This driver is marked as broken for 2 years, and no one cares to make it
compile and work. Now it is time to zap it.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>