library/test: replace LEGACY symbol with BASIC_IMPORT_EXPORT

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index 089333d..db8d004 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -184,7 +184,7 @@
 #endif
 #else /* MBEDTLS_USE_PSA_CRYPTO */
 #if defined(PSA_WANT_ALG_ECDSA)
-#if defined(MBEDTLS_PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_LEGACY)
+#if defined(MBEDTLS_PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_BASIC_IMPORT_EXPORT)
 #define MBEDTLS_PK_CAN_ECDSA_SIGN
 #endif
 #if defined(PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY)