perf evsel: Fix spelling typo

Correct spelling "unsuported" to "unsupported" in
tools/peft/util/evsel.c

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: standby24x7@gmail.com
Cc: trivial@kernel.org
Link: http://lkml.kernel.org/r/1327500312-9520-1-git-send-email-standby24x7@gmail.com
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>