Add device tree binding document for Novatek, focal and Goodix touch drivers. Change-Id: Ic5e2b28dbee78860a00f715047bf99cd4e019b75 Signed-off-by: Vinoth Jayaram <quic_c_vinoja@quicinc.com> Signed-off-by: Raghavendra Ambadas <quic_c_rambad@quicinc.com>