r200: fix bgrx8/xrgb8 blits

r200: fix bgrx8/xrgb8 blits

Since 779cabfc7d022de8b7b9bc7fdac0caffa8646c51 the same txformat table entries
are used for "normal" texturing as well as for blits. However, I forgot to put
in an entry for the bgrx8 (le) and xrgb8 (be) formats - the normal texturing
path can't hit them because the radeon tex format chooser will never chose
them, but we get that format from the dri buffers (at least I assume we got
it from there).
This is untested but essentially addressing the same bug as for radeon.
(I don't think that the second entry per le/be table is actually necessary,
but shouldn't hurt...)

Tested-by: Ian Romanick <ian.d.romanick@intel.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Cc: "11.0" <mesa-stable@lists.freedesktop.org>