lib/test_bitmap: use pr_info() for non-error messages

lib/test_bitmap: use pr_info() for non-error messages

pr_err() messages may be treated as errors by some log readers, so let
us only use them for test failures. For non-error messages, replace them
with pr_info().

Suggested-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>