GPL 3.0 in TCG test code

[Stefan Weil]

Dear all,

some QEMU code under tests/tcg uses GPL 3.0 or later:

tests/tcg/aarch64/semicall.h: * SPDX-License-Identifier: GPL-3.0-or-later
tests/tcg/arm/semicall.h: * SPDX-License-Identifier: GPL-3.0-or-later
tests/tcg/i386/system/boot.S: * SPDX-License-Identifier: GPL-3.0-or-later
tests/tcg/multiarch/arm-compat-semi/semiconsole.c: * 
SPDX-License-Identifier: GPL-3.0-or-later
tests/tcg/multiarch/arm-compat-semi/semihosting.c: * 
SPDX-License-Identifier: GPL-3.0-or-later
tests/tcg/multiarch/float_convd.c: * SPDX-License-Identifier: 
GPL-3.0-or-later
tests/tcg/multiarch/float_convs.c: * SPDX-License-Identifier: 
GPL-3.0-or-later
tests/tcg/multiarch/float_helpers.h: * SPDX-License-Identifier: 
GPL-3.0-or-later
tests/tcg/multiarch/float_madds.c: * SPDX-License-Identifier: 
GPL-3.0-or-later
tests/tcg/multiarch/libs/float_helpers.c: * SPDX-License-Identifier: 
GPL-3.0-or-later
tests/tcg/riscv64/semicall.h: * SPDX-License-Identifier: GPL-3.0-or-later
tests/tcg/x86_64/system/boot.S: * SPDX-License-Identifier: GPL-3.0-or-later

I don't think that there is a conflict with the QEMU license (GPL 2.0 or 
later) because that code is only used in tests.

But maybe it should be mentioned in LICENSE?

Regards,
Stefan