clang-format inconsistencies with checkpatch.pl

[Mickaël Salaün]

Hi,

I would like to use clang-format (with a pinned version, probably 14) to 
keep a consistent coding style, or at least start with one. However, 
there is some inconsistencies with the checkpatch.pl script:

In some cases, goto labels are indented, which checkpatch.pl doesn't like.

checkpatch.pl complains about some functions (e.g. FIXTURE or 
FIXTURE_VARIANT_ADD) that get an open brace just after but without a space.

I also noticed that there is some clang-format configuration lines that 
are commented because of incompatibilities with versions older than 6. 
Shouldn't we require a minimal version, at least the 6th?

About checkpatch.pl, it incorrectly warns about space between function 
name and open parenthesis for *for_each* functions (specifically 
interpreted as "for" statements in .clang-format, e.g. list_for_each_entry).

Regards,
 Mickaël