mtd: nand: ams-delta: convert to platform driver

In its current form, the driver may interfere with different hardware on
different boards if built into the kernel, hence is not suitable for
inclusion into a defconfig, inteded to be usable with multiple OMAP1 cpu and
machine types.

Convert it to a platform driver, that should be free from this issue.

Created and tested against linux-2.6.37-rc5 on Amstrad Delta.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>