perf report: Tidy up the "--parent <regex>" and "--sort parent" call-chain features

Instead of the ambigious 'call' naming use the much more
specific 'parent' naming:

 - rename --call <regex> to --parent <regex>

 - rename --sort call to --sort parent

 - rename [unmatched] to [other] - to signal that this is not
   an error but the inverse set

Also add pagefaults to the default parent-symbol pattern too,
as it's a 'syscall overhead category' in a sense.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>