clk: lmk04832: fix return value check in lmk04832_probe()

In case of error, the function devm_kzalloc() and devm_kcalloc() return
NULL pointer not ERR_PTR(). The IS_ERR() test in the return value check
should be replaced with NULL test.

Fixes: 3bc61cfd ("clk: add support for the lmk04832")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Link: https://lore.kernel.org/r/20210630020322.2555946-1-wanghai38@huawei.com


Reviewed-by: Liam Beguin <lvb@xiphos.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>