clk: Mark clk_core_evict_parent_cache_subtree() 'target' const

Clarify that the 'target' clk isn't being modified, instead it's being
searched for. Mark it const so the function can't modify it.

Signed-off-by: Stephen Boyd <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/clk/clk.c

···
 };
 
 static void clk_core_evict_parent_cache_subtree(struct clk_core *root,
-						struct clk_core *target)
+						const struct clk_core *target)
 {
 	int i;
 	struct clk_core *child;