PM / Runtime: Fix loops in pm_runtime_clk_notify()

The loops over connection ID strings in pm_runtime_clk_notify()
should actually iterate over the strings and not over the elements
of the first of them, so make them behave as appropriate.

This fixes a regression introduced by commit 600b776e
(OMAP1 / PM: Use generic clock manipulation routines for runtime PM).

Reported-and-tested-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>