tcg/LICENSE: Remove out of date claim about TCG subdirectory licensing

Since 2008 the tcg/LICENSE file has not changed: it claims that
everything under tcg/ is BSD-licensed.

This is not true and hasn't been true for years: in 2013 we
accepted the tcg/aarch64 target code under a GPLv2-or-later
license statement. We also have generic vector optimisation
code under the LGPL2.1-or-later, and the TCI backend is
GPLv2-or-later. Further, many of the files are not BSD
licensed but MIT licensed.

We don't really consider the tcg subdirectory to be a distinct part
of QEMU anyway.

Remove the LICENSE file, since claiming false information
about the license of the code is confusing.

Update the main project LICENSE file also to be clearer about
the licenses used by TCG.

Reviewed-by: Richard Henderson <[email protected]>
Signed-off-by: Peter Maydell <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Richard Henderson <[email protected]>

LICENSE

@@ -18,8 +18,9 @@ As of July 2013, contributions under version 2 of the GNU General Public
 License (and no later version) are only accepted for the following files
 or directories: bsd-user/, linux-user/, hw/vfio/, hw/xen/xen_pt*.
 
-3) The Tiny Code Generator (TCG) is released under the BSD license
-   (see license headers in files).
+3) The Tiny Code Generator (TCG) is mostly under the BSD or MIT licenses;
+   but some parts may be GPLv2 or other licenses. Again, see the
+   specific licensing information in each source file.
 
 4) QEMU is a trademark of Fabrice Bellard.