perf tools: Fix PMU term format max value calculation

perf tools: Fix PMU term format max value calculation

Currently the max value of format is calculated by the bits number. It
relies on the continuity of the format.

However, uncore event format is not continuous. E.g. uncore qpi event
format can be 0-7,21.

If bit 21 is set, there is parsing issues as below.

  $ perf stat -a -e uncore_qpi_0/event=0x200002,umask=0x8/
  event syntax error: '..pi_0/event=0x200002,umask=0x8/'
                                    \___ value too big for format, maximum is 511

This patch return the real max value by setting all possible bits to 1.

Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1459365375-14285-1-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>