x86/cpufeatures: Move RETPOLINE flags to word 11

commit a883d624 upstream.

In order to extend the RETPOLINE features to 4, move them to word 11
where there is still room. This mostly keeps DISABLE_RETPOLINE
simple.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[bwh: Backported to 5.10: bits 8 and 9 of word 11 are also free here,
 so comment them accordingly]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>