PM / clk: Print acquired clock name in addition to con_id

Currently the con_id of the acquired clock is printed for debugging
purposes.  But in several cases, the con_id is NULL, which doesn't
provide much debugging information when printed.  These cases are:
  - When explicitly passing a NULL con_id (which means the first clock
    tied to the device, if available),
  - When not using pm_clk_add(), but pm_clk_add_clk() (which takes a
    "struct clk *" directly).

Hence print the actual clock name in addition to (and not instead of;
thanks Grygorii Strashko!) the con_id.

Note that the clock name is not available with legacy clock frameworks,
and the hex pointer address will be printed instead.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Grygorii Strashko <grygorii.strashko@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>