device and dynamic_debug: Use dev_vprintk_emit and dev_printk_emit

Convert direct calls of vprintk_emit and printk_emit to the
dev_ equivalents.

Make create_syslog_header static.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: David S. Miller <davem@davemloft.net>
Tested-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>