[nrf noup] matter: Enable MBEDTLS_LEGACY_CRYPTO_C

-The Kconfig CHIP_CRYPTO_PSA is not a configuration that will enable
 a pure PSA crypto build. There are still features required for
 legacy support. This commit enabled MBEDTLS_LEGACY_CRYPTO_C for now
 to ensure access to ECP (and mbedtls_ecp_muladd)

Signed-off-by: Frank Audun Kvamtrø <frank.kvamtro@nordicsemi.no>

config/nrfconnect/chip-module/Kconfig.defaults

@@ -380,6 +380,7 @@ config MBEDTLS_ECP_C
     default y
 
 config MBEDTLS_ECP_DP_SECP256R1_ENABLED
+    bool
     default y
 
 endif # !CHIP_CRYPTO_PSA
@@ -422,6 +423,10 @@ config MBEDTLS_SSL_COOKIE_C
 config MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
     default y
 
+config MBEDTLS_LEGACY_CRYPTO_C
+    bool
+    default y
+
 # ==============================================================================
 # Logging configuration
 # ==============================================================================