clk: rockchip: Remove useless init of "grf" to -EPROBE_DEFER

When we used to defer setting the "grf" member to
rockchip_clk_get_grf() it was important to init the "grf" member to an
error value in rockchip_clk_init().  With recent changes, we now set
"grf" right in rockchip_clk_init() (two lines below the place where we
initted it).  That makes the old init useless.  Get rid of it.

Fixes: 6f339dc2 ("clk: rockchip: lookup General Register Files in rockchip_clk_init")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>