lm75: Refactor code to fix io error

Use correct resolution by compat table. If dtb is not defined use default 9 bit mode.
11 bit detection is called if 9 bit mode is used.
Sysctl resolution variable is added to change resolution in case.
Some sensors didn't pull ACK while reading from nonexistent registers and it caused I2C
read error and detect failure, so now detect failure does not cause driver break.

Obtained from: Semihalf
Sponsored by: Alstom
Differential revision: https://reviews.freebsd.org/D37497