LF-5491: memory: fsl_ifc: populate child nodes of buses and mfd devices

commit c1084c2773fc1005ed140db625399d5334d94a28 from
https://source.codeaurora.org/external/imx/linux-imx

Commit 257e9d2663d4 was trying to replace the "simple-bus" compatible
with explicit bus populate in the driver.  But of_platform_populate()
only populates child nodes of ifc without populating child buses and
child mfd devices residing under ifc.  Change it to
of_platform_default_populate() to fix the problem.

Fixes: 257e9d2663d4 ("memory: fsl_ifc: populate child devices without relying on simple-bus")

Signed-off-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>