Enable GPU Rasterization with freedreno

Technically the decision is about the driver, not the hw vendor, which
makes the description string a bit funny.  But in the end this decision
is as much about the driver as the hw.

Test: Run ChromeOS on bubs/cheza, and check chrome://gpu
Change-Id: Iaf87cedb9809eb15c535e7b4140f6cedf173fddb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1913061Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
Cr-Commit-Position: refs/heads/master@{#716008}

gpu/config/software_rendering_list.json

@@ -1342,7 +1342,7 @@
     },
     {
       "id": 137,
-      "description": "GPU rasterization on CrOS is blacklisted on anything but Intel, Mali T8/G, Imagination, or AMD GPUs for now.",
+      "description": "GPU rasterization on CrOS is blacklisted on anything but Intel, Mali T8/G, Imagination, Freedreno, or AMD GPU/drivers for now.",
       "cr_bugs": [684094, 996858, 1020500],
       "os": {
         "type": "chromeos"
@@ -1352,6 +1352,7 @@
       ],
       "exceptions": [
         { "vendor_id": "0x8086" },
+        { "gl_vendor": "freedreno" },
         { "gl_renderer": "Mali-T8.*",
           "subpixel_font_rendering": "unsupported"},
         { "gl_renderer": "Mali-G.*",