dm: pcie_fsl: Convert IS_ENABLED() run-time checking to #ifdef

This can avoid build error:
The macro in brackets of the IS_ENABLED(CONFIG_FOO) is only
defined on the platforms that select the CONFIG_FOO, while
it's not defined on platforms that do not select the
CONFIG_FOO.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
1 file changed