static_call: Fix static_call_set_init()

stable inclusion
from stable-5.10.27
commit 394e4fd67946dca595f1b63d37ab32f680df6884
bugzilla: 51493

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

[ Upstream commit 68b1eddd ]

It turns out that static_call_set_init() does not preserve the other
flags; IOW. it clears TAIL if it was set.

Fixes: 9183c3f9 ("static_call: Add inline static call infrastructure")
Reported-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lkml.kernel.org/r/20210318113610.519406371@infradead.org


Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by:   Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>