clk: core: Potentially free connection id

Patch "clk: core: Copy connection id" made it so that the connector id
'con_id' is kstrdup_const()ed to cater to drivers that pass non-constant
connection ids. The patch added the corresponding kfree_const to
__clk_free_clk(), but struct clk's can be freed also via __clk_put().
Add the kfree_const call to __clk_put() and add comments to both
functions to remind that the logic in them should be kept in sync.

Fixes: 253160a8 ("clk: core: Copy connection id")
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>