pk: move MBEDTLS_PK_CAN_ECDSA_SOME macro to pk.h and fix tests

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index 29cac27..b5c02b0 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -177,6 +177,10 @@
 #endif /* PSA_WANT_ALG_ECDSA */
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
 
+#if defined(MBEDTLS_PK_CAN_ECDSA_VERIFY) || defined(MBEDTLS_PK_CAN_ECDSA_SIGN)
+#define MBEDTLS_PK_CAN_ECDSA_SOME
+#endif
+
 /**
  * \brief           Types for interfacing with the debug module
  */