[PATCH] scripts: checkpatch: check unused parameters for function-like macro

[Xining Xu]

If function-like macros do not utilize a parameter, it might result in a
build warning.  In our coding style guidelines, we advocate for utilizing
static inline functions to replace such macros.  This patch verifies
compliance with the new rule.

For a macro such as the one below,

 #define test(a) do { } while (0)

The test result is as follows.

 WARNING: Argument 'a' is not used in function-like macro
 #21: FILE: mm/init-mm.c:20:
 +#define test(a) do { } while (0)

 total: 0 errors, 1 warnings, 8 lines checked

Link: https://lkml.kernel.org/r/20240507032757.146386-3-21cnbao@xxxxxxxxx