dri3: Fix typo in version check

dri3: Fix typo in version check

The have-new-DRI3 codepaths would never actually properly trigger, since
there was a typo in configure.ac which broke the version check. This
went unnoticed but for an error in config.log if you looked closely
enough.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Reported-by: Lukas F. Hartmann <lukas@mntmn.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Fixes: 7aeef2d4efdc ("dri3: allow building against older xcb (v3)")
Cc: Dave Airlie <airlied@redhat.com>