x86/speculation: Move arch_smt_update() call to after mitigation decisions

x86/speculation: Move arch_smt_update() call to after mitigation decisions

arch_smt_update() now has a dependency on both Spectre v2 and MDS
mitigations.  Move its initial call to after all the mitigation decisions
have been made.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
CVE-2018-12126
CVE-2018-12127
CVE-2018-12130

(cherry picked from commit 7c3658b20194a5b3209a143f63bc9c643c6a3ae2)
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>