x86/bugs: Add attack vector controls for TSA

Use attack vector controls to determine which TSA mitigation to use.

  [ bp: Simplify the condition in the select function for better
    readability. ]

Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250709155844.3279471-1-david.kaplan@amd.com