tfm: Fix include order between platform_ns and tfm_api_ns libraries

Fix include order between platform_ns and tfm_api_ns libraries.
platform_ns functions may depend on tfm_api_ns.
This would typically be platform specific IOCTL services added to the
platform_ns library requiring the tfm_platform_ioctl from the
TF-M platform partition exposed in tfm_platform_api.c

Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>