clk: ti: Improve clksel clock bit parsing for reg property

Because of legacy reasons, the TI clksel composite clocks can have
overlapping reg properties, and use a custom ti,bit-shift property.

For the clksel clocks we can start using of the standard reg property
instead of the custom ti,bit-shift property.

To do this, let's add a ti_clk_get_legacy_bit_shift() helper, and make
ti_clk_get_reg_addr() populate the clock bit offset.

This makes it possible to update the devicetree files to use the reg
property one clock at a time.

Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

include/linux/clk/ti.h

@@ -13,11 +13,14 @@
 /**
  * struct clk_omap_reg - OMAP register declaration
  * @offset: offset from the master IP module base address
+ * @bit: register bit offset
  * @index: index of the master IP module
+ * @flags: flags
  */
 struct clk_omap_reg {
 	void __iomem *ptr;
 	u16 offset;
+	u8 bit;
 	u8 index;
 	u8 flags;
 };