memory: fsl_ifc: populate child nodes of buses and mfd devices

Commit 3e25f800 ("memory: fsl_ifc: populate child devices without
relying on simple-bus") 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: 3e25f800

 ("memory: fsl_ifc: populate child devices without relying on simple-bus")
Signed-off-by: Li Yang <leoyang.li@nxp.com>
Link: https://lore.kernel.org/r/20220307204118.19093-1-leoyang.li@nxp.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>