OMAP2+ clock: clean up clkt_clksel.c

This patch cleans up arch/arm/mach-omap2/clkt_clksel.c.  It:

- makes several functions static that are not called outside the file;

- adds documentation;

- makes some code paths easier to read (hopefully), by breaking up
  compound statements and removing redundant checks;

- converts some pr_err()s that indicate clock tree data problems into WARN()s,
  so they are more likely to be noticed;

- and moves omap2_clk_round_rate() back into mach-omap2/clock.c, its proper
  home, since it is not clksel-specific.

Signed-off-by: Paul Walmsley <paul@pwsan.com>

arch/arm/mach-omap2/clock.h

@@ -73,19 +73,20 @@ void omap2_clk_disable_unused(struct clk *clk);
 #define omap2_clk_disable_unused	NULL
 #endif
 
-unsigned long omap2_clksel_recalc(struct clk *clk);
 void omap2_init_clk_clkdm(struct clk *clk);
-void omap2_init_clksel_parent(struct clk *clk);
-u32 omap2_clksel_get_divisor(struct clk *clk);
+
+/* clkt_clksel.c public functions */
 u32 omap2_clksel_round_rate_div(struct clk *clk, unsigned long target_rate,
 				u32 *new_div);
-u32 omap2_clksel_to_divisor(struct clk *clk, u32 field_val);
-u32 omap2_divisor_to_clksel(struct clk *clk, u32 div);
+void omap2_init_clksel_parent(struct clk *clk);
+unsigned long omap2_clksel_recalc(struct clk *clk);
 long omap2_clksel_round_rate(struct clk *clk, unsigned long target_rate);
 int omap2_clksel_set_rate(struct clk *clk, unsigned long rate);
 int omap2_clksel_set_parent(struct clk *clk, struct clk *new_parent);
+
 u32 omap2_get_dpll_rate(struct clk *clk);
 void omap2_init_dpll_parent(struct clk *clk);
+
 int omap2_wait_clock_ready(void __iomem *reg, u32 cval, const char *name);