google/snow: enable clock gating to save power

This enables clock gating to save power on unused IPs.

Change-Id: I9ab2a2535ebb91bb4110390a6f055a67146bdbf9
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/3110
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/mainboard/google/snow/ramstage.c

@@ -220,6 +220,9 @@ static void mainboard_init(device_t dev)
 
 	tmu_init(&exynos5250_tmu_info);
 
+	/* Clock Gating all the unused IP's to save power */
+	clock_gate();
+
 	snow_lcd_vdd();
 	do {
 		udelay(50);