Most FSL PCIe controllers expects 333 MHz PCI reference clock.
This clock is derived from the CCB but in many cases the ref.
clock is not 333 MHz and a divisor needs to be configured.
This adds PEX_CCB_DIV #define which can be defined for each
type of CPU/platform.
Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com>
Reviewed-by: York Sun <york.sun@nxp.com>