Regarding the architecture-specific nature of the warning: I have verified that
this warning is not triggered on x86_64, even with W=1. It appears to
be specific
to the RISC-V toolchain's diagnostic analysis.

Given the other patches in there series, i have to wounder, is the
diagnostic analysis correct? Or is the RISC-V toolchain buggy?

Regardless, converting to ethtool_sprintf() is the correct approach
which does not throw any warning on the both platforms.

I do agree ethtool_sprintf() is better. But we want the commit message
to reflect why we are making this change. Is it because
ethtool_sprintf() is better, or are we working around toolchain bugs?

	Andrew