kvfree(NULL) is safe. NULL check before kvfree() is not needed.
Delete them to simplify the code.

Generated by coccinelle script:
	scripts/coccinelle/free/ifnullfree.cocci
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20220606131401.4053036-1-william.xuanziyang@huawei.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>