Update MTD to that of Linux 2.6.22.1

A lot changed in the Linux MTD code, since it was last ported from
Linux to U-Boot. This patch takes U-Boot NAND support to the level
of Linux 2.6.22.1 and will enable support for very large NAND devices
(4KB pages) and ease the compatibility between U-Boot and Linux
filesystems.

This patch is tested on two custom boards with PPC and ARM
processors running YAFFS in U-Boot and Linux using gcc-4.1.2
cross compilers.

MAKEALL ppc/arm has some issues:
 * DOC/OneNand/nand_spl is not building (I have not tried porting
   these parts, and since I do not have any HW and I am not familiar
   with this code/HW I think its best left to someone else.)

Except for the issues mentioned above, I have ported all drivers
necessary to run MAKEALL ppc/arm without errors and warnings. Many
drivers were trivial to port, but some were not so trivial. The
following drivers must be examined carefully and maybe rewritten to
some degree:
 cpu/ppc4xx/ndfc.c
 cpu/arm926ejs/davinci/nand.c
 board/delta/nand.c
 board/zylonite/nand.c

Signed-off-by: William Juul <william.juul@tandberg.com>
Signed-off-by: Stig Olsen <stig.olsen@tandberg.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>

common/cmd_doc.c

@@ -14,6 +14,7 @@
 #include <linux/mtd/nftl.h>
 #include <linux/mtd/doc2000.h>
 
+#if 0
 #ifdef CFG_DOC_SUPPORT_2000
 #define DoC_is_2000(doc) (doc->ChipID == DOC_ChipID_Doc2k)
 #else
@@ -1629,3 +1630,6 @@ void doc_probe(unsigned long physadr)
 		puts ("No DiskOnChip found\n");
 	}
 }
+#else
+void doc_probe(unsigned long physadr) {}
+#endif