imx: mx6 correct is_soc_rev usage

is_soc_rev should return a bool value, so use "==", but not "-",
change (is_soc_rev(CHIP_REV_1_0) > 0) to (soc_rev() > CHIP_REV_1_0).
This patch also add space between "&" for cpu_type(rev) macro.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>