Add support for AMCC Sequoia PPC440EPx eval board

- Add support for PPC440EPx & PPC440GRx
- Add support for PPC440EP(x)/GR(x) NAND controller
  in cpu/ppc4xx directory
- Add NAND boot functionality for Sequoia board,
  please see doc/README.nand-boot-ppc440 for details
- This Sequoia NAND image doesn't support environment
  in NAND for now. This will be added in a short while.
Patch by Stefan Roese, 07 Sep 2006

include/linux/mtd/compat.h

@@ -31,11 +31,13 @@
 #define max_t(type,x,y) \
 	({ type __x = (x); type __y = (y); __x > __y ? __x: __y; })
 
+#ifndef BUG
 #define BUG() do { \
 	printf("U-Boot BUG at %s:%d!\n", __FILE__, __LINE__); \
 } while (0)
 
 #define BUG_ON(condition) do { if (condition) BUG(); } while(0)
+#endif /* BUG */
 
 #define likely(x)	__builtin_expect(!!(x), 1)
 #define unlikely(x)	__builtin_expect(!!(x), 0)