psa_crypto_helpers: add guard for MBEDTLS_TEST_STATIC_KEY_SLOTS_SUPPORT_RSA_xxx

PSA_KEY_EXPORT_RSA_KEY_PAIR_MAX_SIZE() is not defined when there
is no MBEDTLS_PSA_CRYPTO_CLIENT so we need this guard to
define MBEDTLS_TEST_STATIC_KEY_SLOTS_SUPPORT_RSA_[2048/4096].

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/tests/include/test/psa_crypto_helpers.h b/tests/include/test/psa_crypto_helpers.h
index e7b41b2..2889513 100644
--- a/tests/include/test/psa_crypto_helpers.h
+++ b/tests/include/test/psa_crypto_helpers.h
@@ -471,6 +471,8 @@
 /* A couple of helper macros to verify if MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE is
  * large enough to contain an RSA key pair of the given size. This is meant to be
  * used in test cases where MBEDTLS_PSA_STATIC_KEY_SLOTS is enabled. */
+#if defined(MBEDTLS_PSA_CRYPTO_CLIENT)
+
 #if (MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE >= PSA_KEY_EXPORT_RSA_KEY_PAIR_MAX_SIZE(4096))
 #define MBEDTLS_TEST_STATIC_KEY_SLOTS_SUPPORT_RSA_4096
 #endif
@@ -479,6 +481,8 @@
 #define MBEDTLS_TEST_STATIC_KEY_SLOTS_SUPPORT_RSA_2048
 #endif
 
+#endif /* MBEDTLS_PSA_CRYPTO_CLIENT */
+
 /* Helper macro for the PK module to check whether MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE
  * is large enough to contain 4096 bits RSA key pairs. Of course this check is only
  * necessary if PK relies on PSA (i.e. MBEDTLS_USE_PSA_CRYPTO) to store and manage