clang-format: import style from Linux kernel
clang-format: import style from Linux kernel

The Linux kernel now has an official .clang-format file
available. Import this file to EC codebase.

Changes made:

- Uncommented options that were disabled since kernel targets
  clang-format 4.0, but we have 9.0 in the chroot

- Removed kernel-specific foreach macros

BUG=none
BRANCH=none
TEST=clang-formatted some files, made sure they looked Linux-kernel
like

Change-Id: I8255fad43f965186852f82120ed07ca5f7fff643
Signed-off-by: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1718830
Reviewed-by: Raul E Rangel <9a9c998e11a2655b1de9a05eeeef5f710c0dc7ed@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec