This patch implements code to handle ibs interrupts. If ibs data is
available a raw perf_event data sample is created and sent back to the
userland. This patch only implements the storage of ibs data in the
raw sample, but this could be extended in a later patch by generating
generic event data such as the rip from the ibs sampling data.
V2:
* Added bit mask for msr offsets.
* Added caps field to raw sample format.
* Rebase on Don's NMI patches that introduce register_nmi_handler().
Signed-off-by: Robert Richter <robert.richter@amd.com>