perf c2c: Replace bitmap_weight() with bitmap_empty() where appropriate

perf c2c: Replace bitmap_weight() with bitmap_empty() where appropriate

Some code in builtin-c2c.c calls bitmap_weight() to check if any bit of
a given bitmap is set.

It's better to use bitmap_empty() in that case because bitmap_empty()
stops traversing the bitmap as soon as it finds first set bit, while
bitmap_weight() counts all bits unconditionally.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Klimov <aklimov@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: David Laight <david.laight@aculab.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Joe Perches <joe@perches.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: http://lore.kernel.org/lkml/20220123183925.1052919-13-yury.norov@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>