commit 4c92057661a3412f547ede95715641d7ee16ddac upstream

Add documentation to the Spectre document about the new swapgs variant of
Spectre v1.
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>