licenses: Remove SPDX tags not being license identifier for Linaro

licenses: Remove SPDX tags not being license identifier for Linaro

Per [*]:

  "we're only interested in adopting SPDX for recording the
  licensing info, [not] any other SPDX metadata."

Replace the 'SPDX-FileCopyrightText' and 'SPDX-FileContributor'
tags added by Linaro by 'Copyright (c)' and 'Authors' words
respectively.

[*] https://lore.kernel.org/qemu-devel/20241007154548.1144961-4-berrange@redhat.com/

Inspired-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>