ARM: clk-imx27: Add missing clock for mx2-camera

ARM: clk-imx27: Add missing clock for mx2-camera

During the clock conversion for mx27 the "per4_gate" clock was missed to get
registered as a dependency of mx2-camera driver.

In the old mx27 clock driver we used to have:

DEFINE_CLOCK1(csi_clk, 0, NULL, 0, parent, &csi_clk1, &per4_clk);

,so does the same in the new clock driver

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>