CPTS module of CPSW IP enables timestamp synchronization
using PTP. Enable CPTS feature of CPSW driver.

Available on AM335x, AM437x and DRA7x SoCs.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Acked-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>