clk: Unlink clock if failed to prepare or enable

On failing to prepare or enable a clock, remove the core structure
from the list it has been inserted as it is about to be freed.

This otherwise leads to random crashes when subsequent clocks get
registered, during which parsing of the clock tree becomes adventurous.

Observed with QEMU's RPi-3 emulation.

Fixes: 12ead774 ("clk: Don't try to enable critical clocks if prepare failed")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Michael Turquette <mturquette@baylibre.com>
Link: https://lkml.kernel.org/r/20200505140953.409430-1-maz@kernel.orgSigned-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/clk.c

@@ -3519,6 +3519,9 @@ static int __clk_core_init(struct clk_core *core)
 out:
 	clk_pm_runtime_put(core);
 unlock:
+	if (ret)
+		hlist_del_init(&core->child_node);
+
 	clk_prepare_unlock();
 
 	if (!ret)