Based on the lpc3180 driver, but released as a separate driver for two reasons:
1) I don't have an lpc3180 to test it against, so it might unintentionally break compatibility.
2) It's using a different OOB layout than lpc3180.
Rewritten so that it no longer borrows code from the NXP CDL library. Instead borrowing code from the u-boot port to lpc32xx, written by Kevin Wells.
Tested on lpc3250 (Hitex LPC3250-Stick). OOB layout is compatible with LPCLinux.
Rename nand.h as flash/nand/core.h, chase consumers. The public APIs
need to be sorted out with imp.h, but this allows other changes to
begin improving the separation between policy and mechanism.
Moves #include <target/target.h> and #include "driver.h" into the
internal headers or source files, removing it from <flash/nand/core.h>.
