Remove trademark acknowledgements throughout

Remove trademark acknowledgements throughout

The GNU Coding Standards say:

  "Please do not include any trademark acknowledgements in GNU
  software packages or documentation."

gdb/ChangeLog:
2016-01-12  Pedro Alves  <palves@redhat.com>

	Remove use of the registered trademark symbol throughout.

gdb/gdbserver/ChangeLog:
2016-01-12  Pedro Alves  <palves@redhat.com>

	Remove use of the registered trademark symbol throughout.

gdb/doc/ChangeLog:
2016-01-12  Pedro Alves  <palves@redhat.com>

	Remove use of the registered trademark symbol throughout.