When enabling NAND support for a board, one must also define
CONFIG_SYS_64BIT_VSPRINTF because this is needed in nand_util.c
for correct output.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Cc: Dave Liu <daveliu@freescale.com>
Cc: Ron Madrid <ron_madrid@sbcglobal.net>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>