perf/x86: Fix P6 FP_ASSIST event constraint

According to Intel SDM Volume 3B, FP_ASSIST is limited to Counter 1 only,
not Counter 0.

Tested on a Pentium II.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1210191728570.14552@vincent-weaver-1.um.maine.edu


Signed-off-by: Ingo Molnar <mingo@kernel.org>