hwmon: (vt1211) Convert macros to functions to avoid TOCTOU

hwmon: (vt1211) Convert macros to functions to avoid TOCTOU

The macros IN_FROM_REG, TEMP_FROM_REG, and RPM_FROM_REG evaluate their
arguments multiple times. These macros are used in lockless show functions
involving shared driver data, leading to Time-of-Check to Time-of-Use race
conditions.

For example, RPM_FROM_REG checks if a value is 0 or 255, and then uses it
in a division. If the value is modified by another thread to 0 after the
check but before the division, it causes a divide-by-zero error.

Convert these macros to static functions. This guarantees that arguments
are evaluated only once (pass-by-value), fixing the race conditions.
Adhere to the principle of minimal changes by only converting the specific
macros involved in these lockless contexts.

Link: https://lore.kernel.org/all/CALbr=LYJ_ehtp53HXEVkSpYoub+XYSTU8Rg=o1xxMJ8=5z8B-g@mail.gmail.com/
Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com>
Link: https://lore.kernel.org/r/20251120041331.1917570-1-hanguidong02@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>