updates to checkpatch and clang-format configuration

[pabigot]

Basic cleanup preparatory to addressing #21392 (comment), specifically to update checkpatch to be closer to current Linux, and verifying .clang-format is consistent with Zephyr needs.

FWIW, our .clang-format and LInux differ only in the ForEachMacros list. clang-format transforms those to add a space after the macro name, which gets diagnosed as a style error by checkpatch. The Linux clang-format also makes changes that are rejected by Linux checkpatch (ForEachMacros and other whitespace diagnostics). So it's not clear that clang-format is actually used by Linux.

[zephyrbot]

All checks are passing now.

Tip: The bot edits this comment instead of posting a new one, so you can check the comment's history to see earlier messages.

[chrta]

@pabigot What version of clang-format should be used? I am asking because of lines like this:

#FixNamespaceComments: false # Unknown to clang-format-4.0

[pabigot]

@chrta I have no idea. Those lines are unchanged from the current Linux configuration. It appears 11 is latest; my OS distribution gave me 9.

Since it doesn't seem like Linux actually uses this (since it creates code that doesn't pass checkpatch) I don't think it's useful, and I'm not planning to try to create a configuration that matches Zephyr style, but since it's already in tree it seemed worth getting it updated.

[stephanosio]

This patch introduced a SPDX license identifier-related noise, unless we are now enforcing Linux-style license identifier placement (i.e. in the first line):

-:22: WARNING:SPDX_LICENSE_TAG: Missing or malformed SPDX-License-Identifier tag in line 1
#22: FILE: drivers/interrupt_controller/intc_gicv3.c:1:
+/*

-:25: WARNING:SPDX_LICENSE_TAG: Misplaced SPDX-License-Identifier tag - use line 1 instead
#25: FILE: drivers/interrupt_controller/intc_gicv3.c:4:
+ * SPDX-License-Identifier: Apache-2.0

ADD: #24921 provides a fix.
Fix #24930 merged