net: lwm2m: report resource type / content type at registration

Per LwM2M specification 5.3.1 Register, report "ct=11543" when JSON is
supported. Also, report the resource type as rt="oma.lwm2m" when "ct="
presents.

Signed-off-by: Robert Chou <robert.ch.chou@acer.com>
1 file changed