oprofile: fix install for avr32

There is no perf_events support in the kernel for avr32. The oprofile
package makefile hard codes the list of binaries to install. Unfortunately,
this hard-coded list contains pe_profiling/operf, which is only built when
perf_events support is available.

Fixes autobuild failures such as the following.

  http://autobuild.buildroot.net/results/492/492659bc252395a62e62e6005ed0e86e582dcada/



Signed-off-by: Simon Dawson <spdawson@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>