hwmon: (adm1275) Make sure we are reading enough data for different chips

[ Upstream commit 6d1d41c0

 ]

Issue:
When PEC is enabled, binding adm1272 to the adm1275 would
fail due to PEC error. See below:
adm1275: probe of xxxx failed with error -74

Diagnosis:
Per the datasheet of adm1272, adm1278, adm1293 and amd1294,
PMON_CONFIG (0xd4) is 16bits wide. On the other hand,
PMON_CONFIG (0xd4) for adm1275 is 8bits wide. The driver should not
assume everything is 8bits wide and read only 8bits from it.

Solution:
If it is adm1272, adm1278, adm1293 and adm1294, use i2c_read_word.
Else, use i2c_read_byte

Testing:
Binding adm1272 to the driver.
The change is only tested on adm1272.

Signed-off-by: Chu Lin <linchuyuan@google.com>
Link: https://lore.kernel.org/r/20200709040612.3977094-1-linchuyuan@google.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>