trusted-firmware-m: select PSA_CRYPTO_CLIENT when BUILD_WITH_TFM

TF-M is a PSA API provider alternative to Mbed TLS one. As
a consequence when CONFIG_BUILD_WITH_TFM is set
CONFIG_PSA_CRYPTO_CLIENT should be set as well.

Signed-off-by: Valerio Setti <vsetti@baylibre.com>