perf tools: Drop unneeded bitmap_zero() calls

perf tools: Drop unneeded bitmap_zero() calls

bitmap_zero() is called after bitmap_alloc() in perf code. But
bitmap_alloc() internally uses calloc() which guarantees that allocated
area is zeroed. So following bitmap_zero is unneeded. Drop it.

This happened because of confusing name for bitmap allocator. It
should has name bitmap_zalloc instead of bitmap_alloc.

This series:

  https://lkml.org/lkml/2018/6/18/841

introduces a new API for bitmap allocations in kernel, and functions
there are named correctly. Following patch propogates the API to tools,
and fixes naming issue.

Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andriy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Link: http://lkml.kernel.org/r/20180623073502.16321-1-ynorov@caviumnetworks.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>