Implement rudimentary IVB perf support. The SDM states its identical
to SNB with exception of the exact event tables, but a quick look
suggests they're similar enough.

Also mark SNB-EP as broken for now.
Requested-and-tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338884803.28282.153.camel@twinsSigned-off-by: Ingo Molnar <mingo@kernel.org>