clk: clk-apple-nco: Add NULL check in applnco_probe

clk: clk-apple-nco: Add NULL check in applnco_probe

[ Upstream commit 969c765e2b508cca9099d246c010a1e48dcfd089 ]

Add NULL check in applnco_probe, to handle kernel NULL pointer
dereference error.

Fixes: 6641057d5dba ("clk: clk-apple-nco: Add driver for Apple NCO")
Signed-off-by: Charles Han <hanchunchao@inspur.com>
Link: https://lore.kernel.org/r/20241114072820.3071-1-hanchunchao@inspur.com
Reviewed-by: Martin Povišer <povik+lin@cutebit.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>