pk: guard mbedtls_pk_wrap_as_opaque() with CRYPTO_CLIENT instead of USE_PSA

Albeit this function is very likely to be deprecated soon (#8848)
it is still used in test suites to generate opaque keys so its
guard must be aligned as well in order to have a better test
coverage of opaque keys.

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/pk.c b/library/pk.c
index 87b1d8f..d52c77d 100644
--- a/library/pk.c
+++ b/library/pk.c
@@ -1080,7 +1080,7 @@
     return ctx->pk_info->type;
 }
 
-#if defined(MBEDTLS_USE_PSA_CRYPTO)
+#if defined(MBEDTLS_PSA_CRYPTO_CLIENT)
 /*
  * Load the key to a PSA key slot,
  * then turn the PK context into a wrapper for that key slot.
@@ -1199,5 +1199,5 @@
 #endif /* !MBEDTLS_PK_HAVE_ECC_KEYS && !MBEDTLS_RSA_C */
     return MBEDTLS_ERR_PK_TYPE_MISMATCH;
 }
-#endif /* MBEDTLS_USE_PSA_CRYPTO */
+#endif /* MBEDTLS_PSA_CRYPTO_CLIENT */
 #endif /* MBEDTLS_PK_C */