x86: fix AMDC1E and XTOPOLOGY conflict in cpufeature

Impact: fix xsave slowdown regression

Fix two features from conflicting in feature bits.

Fixes this performance regression:

   Subject: cpu2000(both float and int) 13% regression with 2.6.28-rc1
   http://lkml.org/lkml/2008/10/28/36

Reported-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Bisected-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>