mce, amd: Add helper functions to setup APIC

This patch reworks and cleans up mce_amd_feature_init() by
introducing helper functions to setup and check the LVT offset.
It also fixes line endings in pr_err() calls.

Signed-off-by: Robert Richter <robert.richter@amd.com>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <1288015419-29543-4-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>