inteltool: add more hardware IDs and PCIEXBAR/PXPEPBAR read support

Add IDs of some SNB and Haswell chips; use more descriptive names.
Add PCIEXBAR and PXPEPBAR read support for SNB/IVB/Haswell.

Change-Id: I16753bf90061fc2065b813b1c2169e7b7bcc89e8
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-on: http://review.coreboot.org/7360
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Mathias Krause <minipli@googlemail.com>