tegra: Add a delay in clock_start_periph_pll()

This function enables a peripheral clock and then immediately sets its
divider. Add a delay to allow the clock to settle first. This matches the
delay in other places which do a similar thing.

Without this, the I2S device on Nyan does not init properly.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/arch/arm/mach-tegra/clock.c b/arch/arm/mach-tegra/clock.c
index 0963307..dc5f16b 100644
--- a/arch/arm/mach-tegra/clock.c
+++ b/arch/arm/mach-tegra/clock.c
@@ -477,6 +477,7 @@
 
 	reset_set_enable(periph_id, 1);
 	clock_enable(periph_id);
+	udelay(2);
 
 	effective_rate = clock_adjust_periph_pll_div(periph_id, parent, rate,
 						 NULL);