AT91 CPU9260 CPU9G20 Fix compile warnings

This change fixes the compiler warning

nand_util.c:45:2: warning: #warning Please define CONFIG_SYS_64BIT_VSPRINTF
  for correct output!

Signed-off-by: Eric Benard <eric@eukrea.com>
Signed-off-by: Tom Rix <Tom.Rix@windriver.com>