r600g,radeonsi: Always use GTT again for PIPE_USAGE_STREAM buffers

Putting those in VRAM can cause long pauses due to buffers being moved
into / out of VRAM.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=84662
Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

src/gallium/drivers/radeon/r600_buffer_common.c

@@ -110,11 +110,13 @@ bool r600_init_resource(struct r600_common_screen *rscreen,
 	enum radeon_bo_flag flags = 0;
 
 	switch (res->b.b.usage) {
+	case PIPE_USAGE_STREAM:
+		flags = RADEON_FLAG_GTT_WC;
+		/* fall through */
 	case PIPE_USAGE_STAGING:
 		/* Transfers are likely to occur more often with these resources. */
 		res->domains = RADEON_DOMAIN_GTT;
 		break;
-	case PIPE_USAGE_STREAM:
 	case PIPE_USAGE_DYNAMIC:
 		/* Older kernels didn't always flush the HDP cache before
 		 * CS execution