libgomp, nvptx: report USM supported

libgomp/ChangeLog:

	* plugin/plugin-nvptx.c (GOMP_OFFLOAD_supported_features): Allow
	GOMP_REQUIRES_UNIFIED_ADDRESS and GOMP_REQUIRES_UNIFIED_SHARED_MEMORY.

diff --git a/libgomp/plugin/plugin-nvptx.c b/libgomp/plugin/plugin-nvptx.c
index dd490b2ae2a..e77c6a87930 100644
--- a/libgomp/plugin/plugin-nvptx.c
+++ b/libgomp/plugin/plugin-nvptx.c
@@ -1260,11 +1260,14 @@ GOMP_OFFLOAD_fini_device (int n)
   return true;
 }
 
-/* Indicate which GOMP_REQUIRES_* features are supported, currently none.  */
+/* Indicate which GOMP_REQUIRES_* features are supported.  */
 
 bool
 GOMP_OFFLOAD_supported_features (unsigned int *mask)
 {
+  *mask &= ~(GOMP_REQUIRES_UNIFIED_ADDRESS
+             | GOMP_REQUIRES_UNIFIED_SHARED_MEMORY);
+
   return (*mask == 0);
 }