ipmi: kcs_bmc: handle devm_kasprintf() failure case

mainline inclusion
from mainline-5.0
commit 42c7c6ef
category: bugfix
bugzilla: 11934
CVE: NA

-------------------------------------------------

devm_kasprintf() may return NULL if internal allocation failed so this
assignment is not safe. Moved the error exit path and added the !NULL
which then allows the devres manager to take care of cleanup.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Fixes: cd2315d4 ("ipmi: kcs_bmc: don't change device name")
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Reviewed-by: Haiyue Wang <haiyue.wang@linux.intel.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Xuefeng <Wang&lt;wxf.wang@hisilicon.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>