net: bt: Fix not showing any logs

Including logging/sys_log.h before net_core.h prevents SYS_LOG_LEVEL,
etc, to be set properly.

Change-Id: Iaa7aa98110aa455162836be1d9560fbfc03569df
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
diff --git a/subsys/net/ip/l2/bluetooth.c b/subsys/net/ip/l2/bluetooth.c
index e7b3ca9..c3308d0 100644
--- a/subsys/net/ip/l2/bluetooth.c
+++ b/subsys/net/ip/l2/bluetooth.c
@@ -25,8 +25,6 @@
 #include <string.h>
 #include <errno.h>
 
-#include <logging/sys_log.h>
-
 #include <board.h>
 #include <device.h>
 #include <init.h>