atomic: wrap atomic.h file from Zephyr
atomic: wrap atomic.h file from Zephyr

Create a wrapper file for atomic.h from Zephyr. It needs including
atomic.h file from CrosEC and definding atomic_get function.

The atomic_*_bit functions can be used in e.g. usb_pd_timer file.
This approach should simplify checking flags when there are more than
32 values.

BUG=b:208435177
TEST=zmake testall & make buildall
BRANCH=none

Signed-off-by: Dawid Niedzwiecki <73bc8c219b84b29e82d4338ec2e55b540c845bc6@semihalf.com>
Change-Id: I86a4e800ce3186f8635da50f7f93d81519f8b34b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3500592
Reviewed-by: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>
Commit-Queue: Dawid Niedzwiecki <f5bfc434019aa486188a171fe04a7dfcd4b6637d@google.com>

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