target/arm: Untabify translate.c

Untabify the arm translate.c. This affects only some lines,
mostly comments, in the iwMMXt code. We've never touched
that code in years, so it's not going to get fixed up
by our "change when touched" process, and a bulk change
is not going to be too disruptive.

This commit was produced using Emacs "untabify"; it is
a whitespace-only change.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Message-id: 20180821165215.29069-2-peter.maydell@linaro.org