perf tools: Fix documentation of verbose options

Option doesn't take a value, make sure the man pages agree. For example:

  $ perf evlist --verbose=1
   Error: option `verbose' takes no value
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210226183145.1878782-1-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-evlist.txt

@@ -29,7 +29,7 @@ OPTIONS
 	Show just the sample frequency used for each event.
 
 -v::
---verbose=::
+--verbose::
 	Show all fields.
 
 -g::

tools/perf/Documentation/perf-ftrace.txt

@@ -28,8 +28,8 @@ OPTIONS
 	specified: function_graph or function.
 
 -v::
---verbose=::
-        Verbosity level.
+--verbose::
+        Increase the verbosity level.
 
 -F::
 --funcs::

tools/perf/Documentation/perf-kallsyms.txt

@@ -20,5 +20,5 @@ modules).
 OPTIONS
 -------
 -v::
---verbose=::
+--verbose::
 	Increase verbosity level, showing details about symbol table loading, etc.

tools/perf/Documentation/perf-trace.txt

@@ -97,8 +97,8 @@ filter out the startup phase of the program, which is often very different.
 	Filter out events for these pids and for 'trace' itself (comma separated list).
 
 -v::
---verbose=::
-        Verbosity level.
+--verbose::
+        Increase the verbosity level.
 
 --no-inherit::
 	Child tasks do not inherit counters.