ARM: tegra30: clock: implement PLLD2 support

PLLD2 is a simple clock (controlled by 2 registers) and appears starting
from T30. Primary use of PLLD2 is as main HDMI clock parent.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
diff --git a/arch/arm/mach-tegra/clock.c b/arch/arm/mach-tegra/clock.c
index 7f31630..575da2b 100644
--- a/arch/arm/mach-tegra/clock.c
+++ b/arch/arm/mach-tegra/clock.c
@@ -768,6 +768,9 @@
 	pll_rate[CLOCK_ID_SFROM32KHZ] = 32768;
 	pll_rate[CLOCK_ID_OSC] = clock_get_rate(CLOCK_ID_OSC);
 	pll_rate[CLOCK_ID_CLK_M] = clock_get_rate(CLOCK_ID_CLK_M);
+#ifndef CONFIG_TEGRA20
+	pll_rate[CLOCK_ID_DISPLAY2] = clock_get_rate(CLOCK_ID_DISPLAY2);
+#endif
 
 	debug("Osc = %d\n", pll_rate[CLOCK_ID_OSC]);
 	debug("CLKM = %d\n", pll_rate[CLOCK_ID_CLK_M]);