x86/bugs: Report properly retpoline+IBRS

x86/bugs: Report properly retpoline+IBRS

If the retpoline fallback is activated we want to properly
report that both of them are on.

This involves a bit of dance where we do not change
the spectre_v2_enabled ever again. But we still need the logic
to detect whether IBRS + retpoline is enabled. To make it
easier we change the name of the function to be more obvious.

OraBug: 27897282
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: John Haxby <john.haxby@oracle.com>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
---
v2: Remove the pr_err('Spectre v2 mitigation IBRS is set.\n')
    Make the retpoline_only_enabled optimized.

Signed-off-by: Brian Maly <brian.maly@oracle.com>
Conflicts:
	arch/x86/kernel/cpu/spec_ctrl.c