st/dri: don't set queryDmaBufFormats/queryDmaBufModifiers if the driver does not...

st/dri: don't set queryDmaBufFormats/queryDmaBufModifiers if the driver does not implement it

This is equivalent to commit a65db0ad1c3, but for dri_kms_init_screen. Without
this gbm_dri_is_format_supported always returns false.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104926
Fixes: e14fe41e0bf ("st/dri: implement createImageFromRenderbuffer(2)")
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Tested-by: Adam Williamson <adamwill@fedoraproject.org>