Documentation: Use UTF-8 encoding and fix one wrong encoding

At least for Linux distributions UTF-8 is now standard,
so the QEMU documentation should use this encoding, too.

Even if there was currently only a single special character
using ISO-8859-1, this might change in the future.

So the texinfo keywords @documentlanguage and
@documentencoding now document the language and the
encoding. The special character was changed to UTF-8
(it could also have been changed to an x, but the
original cross looks really nice if it is displayed
correctly).

These changes fix the html presentation at
http://www.qemu.org/qemu-doc.html#SEC65
(ARM System emulator).
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

qemu-doc.texi

 \input texinfo @c -*- texinfo -*-
 @c %**start of header
 @setfilename qemu-doc.info
+
+@documentlanguage en
+@documentencoding UTF-8
+
 @settitle QEMU Emulator User Documentation
 @exampleindent 0
 @paragraphindent 0
@@ -1831,7 +1835,7 @@ MV88W8xx8 Ethernet controller
 @item
 MV88W8618 audio controller, WM8750 CODEC and mixer
 @item
-12864 display with brightness control
+128×64 display with brightness control
 @item
 2 buttons, 2 navigation wheels with button function
 @end itemize

qemu-tech.texi

 \input texinfo @c -*- texinfo -*-
 @c %**start of header
 @setfilename qemu-tech.info
+
+@documentlanguage en
+@documentencoding UTF-8
+
 @settitle QEMU Internals
 @exampleindent 0
 @paragraphindent 0