scripts/cocci: add Zephyr macro file

Zephyr uses some defines to provide additional information about the
item being declared.  When unrecognized these can confuse the
Coccinelle parser so that it does not apply semantic patches in
situations where they should be applied.

Add a macro file that extends the Coccinelle builtin macro file with
some identifiers that are specific to Zephyr.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>