perf options: Check v type in OPT_U?INTEGER

To avoid problems like the one fixed by Stephane Eranian in 3de29cab, now
we'll got this instead:

	bench/sched-messaging.c:259: error: negative width in bit-field ‘<anonymous>’
	bench/sched-messaging.c:261: error: negative width in bit-field ‘<anonymous>’

Which is rather cryptic, but is how BUILD_BUG_ON_ZERO works, so kernel
hackers should be already used to this.

With it in place found some problems, fixed by changing the affected
variables to sensible types or changed some OPT_INTEGER to OPT_UINTEGER.

Next csets will go thru converting each of the remaining OPT_ so that
review can be made easier by grouping changes per type per patch.

Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>