Ivybridge: fix workaround and enable PAIR

MCHBAR 0x5f10[7:0] should be set to 0x30 for ivybridge
and 0x20 for sandybridge.  Move this code to ramstage
and set it per-chipset.

Power Aware Interrupt Routing is supported in ivybridge,
enable it and set fixed priority.

Boot on ivybridge device and read MCHBAR 0x5f10:

mmio_read8 0xfed15f10
0x30

And verify PAIR is enabled (bit4=1):

mmio_read8 0xfed15418
0x24

Change-Id: If017d5ce2bd5ab5092c86f657434f2b645ee6613
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/1303
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2 files changed