sys: util: add sys_ prefix to SIGN, gcd, and lcm utils

[kartben]

As per our naming conventions for public symbols, these utility functions and macros should be prefixed with "sys_".

These were introduced with #98875 with a lack of prefix.

[aescolar]

By the way, this fix is needed to be able to build https://github.com/zephyrproject-rtos/zephyr/blob/main/drivers/usb_c/vbus/usbc_vbus_adc.c#L99

[ngphibang]

Thank you @kartben. Sorry that we didn't know this rule before #98875 is merged. However, should we do the same for all other macros in util.h, such as MIN/MAX(), min/max, min3/max3(), DIV_ROUND_CLOSEST(), etc. it seems all of them don't have a SYS_/sys_ prefix ?

[sonarqubecloud]

Quality Gate passed

Issues
4 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[kartben]

Thank you @kartben. Sorry that we didn't know this rule before #98875 is merged.

No worries!

However, should we do the same for all other macros in util.h, such as MIN/MAX(), min/max, min3/max3(), DIV_ROUND_CLOSEST(), etc. it seems all of them don't have a SYS_/sys_ prefix ?

The rule is for new APIs being introduced. Renaming existing API is unfortunately not really possible without breaking LOTS of users :)

[fabiobaltieri]

However, should we do the same for all other macros in util.h, such as MIN/MAX(), min/max, min3/max3(), DIV_ROUND_CLOSEST(), etc. it seems all of them don't have a SYS_/sys_ prefix ?

Yeah I don't think that'd be a good idea. In general, I don't think we should blindly follow these rules without applying common sense first, some of these macros are well used in Linux and we have a lot of developers working cross-project, having different convention just makes it harder for them carry over and add distractions when doing code reviews.

Probably no big deal for this one, there is a linux counterpart but it's not as commonly used as min/max though honestly I would leave it as is.