busybox: enable log level configuration in syslog-startup.conf and script

It's possible to configure busybox syslog to only log messages above a
certain level, expose this functionality through the syslog-startup.conf
and syslog init script.

Valid values are 1-8 inclusive.

(From OE-Core rev: 921dfd1a2bc6ad2867da13d2b669288f9788a088)

Signed-off-by: Joshua Lock <josh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/busybox/files/syslog

@@ -40,6 +40,9 @@ if [ -f /etc/syslog-startup.conf ]; then
 	if [ "$REDUCE" = "yes" ]; then
 		SYSLOG_ARGS="$SYSLOG_ARGS -S"
 	fi
+	if [ -n "$LOGLEVEL" ]; then
+	    SYSLOG_ARGS="$SYSLOG_ARGS -l $LOGLEVEL"
+	fi
 else
 	# default: log to 16K shm circular buffer
 	SYSLOG_ARGS="-C"

meta/recipes-core/busybox/files/syslog-startup.conf

@@ -9,3 +9,4 @@ REDUCE=no			# reduce-size logging
 #ROTATEGENS=3			# keep X generations of rotated logs
 BUFFERSIZE=64			# size of circular buffer [kByte]
 FOREGROUND=no			# run in foreground (don't use!)
+#LOGLEVEL=5			# local log level (between 1 and 8)