anv/batch_chain: Improve write_reloc

anv/batch_chain: Improve write_reloc

The old version wasn't properly handling large addresses where we have to
sign-extend to get it into the "canonical form" expected by the hardware.
Also, the new version is capable of doing a clflush of the newly written
reloc if requested.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Cc: "13.0" <mesa-stable@lists.freedesktop.org>
(cherry picked from commit 095c48a496fccdd95821ee426d70674bc75dc6af)