oprofile: add support for Core i7 and Atom

The registers are about the same as other Family 6 CPUs
so we only need to add detection.

I'm not completely happy with calling Nehalem Core i7 because
there will be undoubtedly other Nehalem based CPUs
in the future with different marketing names, but it's
the best we got for now.

Requires updated oprofile userland for the new event files.

If you don't want to update right now you can also use
oprofile.force_arch_perfmon=1 (added in the next patch) with 0.9.4

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>