Add CSI2 clock struct for handling it with clock API when TI PM is disabled.

linux-omap source commit is 8b20f4498928459276bd3366e3381ad595d23432.
Signed-off-by: Sergio Aguirre <saaguirre@ti.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>