modules: tfm: add required selection and dependencies

BUILD_WITH_TFM needs to depend on
ARM_TRUSTZONE_M, which is selected
by the SoC or Board definition. In
addition to that we add an imply
statement for INIT_ARCH_HW_AT_BOOT
because Zephyr will be chain-loaded
by TF-M, and needs to cleanup its
core ARCH registers that might be
left in non-reset state.

Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>