clk: gpio: Get parent clk names in of_gpio_clk_setup()

Get parent clk names in of_gpio_clk_setup() and store the names
in struct clk_gpio_delayed_register_data instead of doing it from
the clk provider's get() callback. of_clk_get_parent_name() can't
be called in struct of_clk_provider's get() callback since it may
make a call to of_clk_get_from_provider() and this in turn tries
to recursively lock of_clk_mutex.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Cc: Sergej Sawazki <ce3a@gmx.de>
Fixes: 0a4807c2 ("clk: Make of_clk_get_parent_name() robust with #clock-cells = 1")
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>