virgl: Assume sRGB write control for older guest kernels or virglrenderer hosts

When the host virglrenderer is an older version that doesn't check the sRGB write
control feature, or when the guest kernel doesn't support CAPS v2, then the guest
will only report support for GL 2.1 on a GL 3.3 host, even though it was supporting
3.3 with earlier guest mesa versions.

By also checking the host feature check version this regression can be avoided.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110921


Fixes: 2845939d
   virgl: Set sRGB write control CAP based on host capabilities

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
(cherry picked from commit 2b87753a)