hwmon: (lm90) Reduce maximum conversion rate for G781

stable inclusion
from stable-v5.10.96
commit b48a05cee2c05e021036305b774ddf19dfb532b4
bugzilla: https://gitee.com/openeuler/kernel/issues/I55NWB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b48a05cee2c05e021036305b774ddf19dfb532b4



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[ Upstream commit a66c5ed5 ]

According to its datasheet, G781 supports a maximum conversion rate value
of 8 (62.5 ms). However, chips labeled G781 and G780 were found to only
support a maximum conversion rate value of 7 (125 ms). On the other side,
chips labeled G781-1 and G784 were found to support a conversion rate value
of 8. There is no known means to distinguish G780 from G781 or G784; all
chips report the same manufacturer ID and chip revision.
Setting the conversion rate register value to 8 on chips not supporting
it causes unexpected behavior since the real conversion rate is set to 0
(16 seconds) if a value of 8 is written into the conversion rate register.
Limit the conversion rate register value to 7 for all G78x chips to avoid
the problem.

Fixes: ae544f64 ("hwmon: (lm90) Add support for GMT G781")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>