sfc_ef100: potential dereference of null pointer

stable inclusion
from stable-v5.10.88
commit 734a3f3106053ee41cecae2a995b3d4d0c246764
bugzilla: 186058 https://gitee.com/openeuler/kernel/issues/I4QW6A

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=734a3f3106053ee41cecae2a995b3d4d0c246764



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[ Upstream commit 407ecd1b ]

The return value of kmalloc() needs to be checked.
To avoid use in efx_nic_update_stats() in case of the failure of alloc.

Fixes: b593b6f1 ("sfc_ef100: statistics gathering")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>