qemu_file: Make qemu_file_is_writable() static

It is not used outside of qemu_file, and it shouldn't.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230530183941.7223-19-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2 files changed