PCIE2 and PCIE3 are decided by corresponing bit in devdisr instead of PCIE1 bit

PCIE2 and PCIE3 should be decided by corresponing bit in devdisr instead of
PCIE1 bit.
On MPC8572DS board, PCIE refers to PCIE1.
Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>