lib/tlibio: Fix a build warning

lib/tlibio: Fix a build warning

Remove the following warning message.

  ===============================
  tlibio.c: In function 'lio_set_debug':
  tlibio.c:212:1: warning: type of 'level' defaults to 'int' [-Wimplicit-int]
   lio_set_debug(level)
   ^
  ==============================

Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>