clk: tegra: add clock support for Tegra20

Add Tegra20 clock support based on common clock framework.

Signed-off-by: Prashant Gaikwad <pgaikwad@nvidia.com>
[swarren: s/1GHz/100MHz/ in call to tegra_clk_plle() to fix PCIe,
implemented KBC clock, ensure all OF lookups return valid cookies i.e.
an explicit error pointer or valid pointer not NULL, adapt to renames
in earlier patches, fixed some checkpatch issues.]
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

drivers/clk/tegra/Makefile

@@ -6,3 +6,5 @@ obj-y					+= clk-periph-gate.o
 obj-y					+= clk-pll.o
 obj-y					+= clk-pll-out.o
 obj-y					+= clk-super.o
+
+obj-$(CONFIG_ARCH_TEGRA_2x_SOC)         += clk-tegra20.o

drivers/clk/tegra/clk.h

@@ -487,4 +487,10 @@ void tegra_init_from_table(struct tegra_clk_init_table *tbl,
 void tegra_init_dup_clks(struct tegra_clk_duplicate *dup_list,
 		struct clk *clks[], int clk_max);
 
+#ifdef CONFIG_ARCH_TEGRA_2x_SOC
+void tegra20_clock_init(struct device_node *np);
+#else
+static inline void tegra20_clock_init(struct device_node *np) {}
+#endif /* CONFIG_ARCH_TEGRA_2x_SOC */
+
 #endif /* TEGRA_CLK_H */