mbedtls: fix mbed-psa link missing

mbed-psa provides one mbed psa implementation which mbedtls needs to link.
For example, mbedtls_hardware_poll (mbedtls mbed_trng.cpp) invokes trng_init
and friends which are implemented in mbed-psa psa_hrng.c.

Author: ccli8

connectivity/mbedtls/CMakeLists.txt

@@ -115,7 +115,12 @@ target_compile_definitions(mbed-mbedtls
         MBED_CONF_MBEDTLS_PRESENT=1
 )
 
-target_link_libraries(mbed-mbedtls PUBLIC mbed-core-flags)
+target_link_libraries(mbed-mbedtls
+    PUBLIC
+        mbed-core-flags
+    INTERFACE
+        $<$<IN_LIST:PSA_Target,${MBED_TARGET_LABELS}>:mbed-psa>
+)
 
 # Workaround for https://github.com/ARMmbed/mbedtls/issues/1077
 # which affects cores without __thumb2__ set by the compiler