apic, x86: Use BIOS settings for IBS and MCE threshold interrupt LVT offsets

We want the BIOS to setup the EILVT APIC registers. The offsets
were hardcoded and BIOS settings were overwritten by the OS.
Now, the subsystems for MCE threshold and IBS determine the LVT
offset from the registers the BIOS has setup. If the BIOS setup
is buggy on a family 10h system, a workaround enables IBS. If
the OS determines an invalid register setup, a "[Firmware Bug]:
" error message is reported.

We need this change also for upcomming cpu families.

Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1286360874-1471-3-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>