x86/bugs/module: Provide retpoline_modules_only parameter to fail non-retpoline modules

x86/bugs/module: Provide retpoline_modules_only parameter to fail non-retpoline modules

This allows developers to have right away a mechanism to see
if their module is incorrect.

Note that we enable this regardless whether the OS is using
retpoline or IBRS. This is on purpose.

Orabug: 28071992
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
---
v2: s/nonretpoline_fail/retpoline_modules_only/

Signed-off-by: Brian Maly <brian.maly@oracle.com>