PM: clk: remove unused of_pm_clk_add_clk()

The last use of of_pm_clk_add_clk() was removed by 2019's
commit fe00f890 ("irqchip/gic-pm: Update driver to use
clk_bulk APIs")

Remove it.

Note that the plural version of_pm_clk_add_clks() is still being
used and is left.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://patch.msgid.link/20250224010610.187503-1-linux@treblig.org


Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>