gallium/radeon: remove separate BE path in r600_translate_colorswap

gallium/radeon: remove separate BE path in r600_translate_colorswap

After further testing, it appears there is no need for
separate BE path in r600_translate_colorswap()

The only fix remaining is the change of the last if statement, in the 4
channels case. Originally, it contained an invalid swizzle configuration
that never got hit, in LE or BE. So the fix is relevant for both systems.

This patch adds an additional 120 available visuals for LE and BE,
as seen in glxinfo

v2:
Tested for regressions by running piglit gpu.py with CAICOS (r600g) on
x86-64 machine. No regressions found.

Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Cc: "11.1 11.2" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>