ARM: configs: keystone: enable cpts

Enable CPTS support which is present in Network Coprocessor Gigabit
Ethernet (GbE) Switch Subsystem.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>