clk: introduce enable_count

As what Linux Kernel 5.3.0 provides when enable/disable clk,
there is an enable_count in clk_core_disable/enable. Introduce
enable_count to track the clk enable/disable count when
clk_enable/disable for CCF. And Initialize enable_count to 0 when
register the clk.

And clk tree dump with enable_count will be supported, it will
be easy for us to check the clk status with enable_count

Signed-off-by: Peng Fan <peng.fan@nxp.com>

drivers/clk/clk.c

@@ -40,6 +40,7 @@ int clk_register(struct clk *clk, const char *drv_name,
 		return ret;
 	}
 
+	clk->enable_count = 0;
 	/* Store back pointer to clk from udevice */
 	clk->dev->uclass_priv = clk;
 

drivers/clk/clk_fixed_rate.c

@@ -27,6 +27,7 @@ static int clk_fixed_rate_ofdata_to_platdata(struct udevice *dev)
 	/* Make fixed rate clock accessible from higher level struct clk */
 	dev->uclass_priv = clk;
 	clk->dev = dev;
+	clk->enable_count = 0;
 
 	return 0;
 }

include/clk.h

@@ -61,6 +61,7 @@ struct clk {
 	struct udevice *dev;
 	long long rate;	/* in HZ */
 	u32 flags;
+	int enable_count;
 	/*
 	 * Written by of_xlate. In the future, we might add more fields here.
 	 */