powerpc/913x: Add config flag for bootdelay

CONFIG_BOOTDELAY is missing from board header file. Add this macro
to enable counting down of auto boot.

Signed-off-by: Harninder Rai <harninder.rai@freescale.com>
[York Sun: Add commit message]
Reviewed-by: York Sun <yorksun@freescale.com>
2 files changed