modules: trusted-firmware-m: fix dependencies for isolation level

Do not allow the TFM_ISOLATION_LEVEL to be non-hidden option,
if the TFM_IPC (PSA_API) option is not set, since, in that case,
only Isolation Level 1 is supported.

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