x86/bugs: Fix spectre_v2 mitigation default on Intel

Commit

  480e803d ("x86/bugs: Restructure spectre_v2 mitigation")

inadvertently changed the spectre-v2 mitigation default from eIBRS to IBRS on
Intel. While splitting the spectre_v2 mitigation in select/update/apply
functions, eIBRS and IBRS selection logic was separated in select and update.

This caused IBRS selection to not consider that eIBRS mitigation is already
selected, fix it.

Fixes: 480e803d ("x86/bugs: Restructure spectre_v2 mitigation")
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250520-eibrs-fix-v1-1-91bacd35ed09@linux.intel.com