wifi: airo: do not assign -1 to unsigned char

stable inclusion
from stable-v5.10.157
commit 8d39913158ad9e59642672ac03822848582c5767
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7MU59

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8d39913158ad9e59642672ac03822848582c5767



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[ Upstream commit e6cb8769 ]

With char becoming unsigned by default, and with `char` alone being
ambiguous and based on architecture, we get a warning when assigning the
unchecked output of hex_to_bin() to that unsigned char. Mark `key` as a
`u8`, which matches the struct's type, and then check each call to
hex_to_bin() before casting.

Cc: Kalle Valo <kvalo@kernel.org>
Cc: linux-wireless@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221024162843.535921-1-Jason@zx2c4.com


Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>