In preparation for adding support for the QN908x cpus, this patch adds
a pristine copy of the vendor SDK files needed for initial support.
The only modification to these files is to add '#ifdef __cplusplus'
guards to all the header files, even if not needed or already
present as '#if defined(__cplusplus)', to make sure
./dist/tools/externc/check.sh check passes.
These files are located under vendor/ directories (both
cpu/qn908x/include/vendor/ and cpu/qn908x/vendor/) and are part of NXP's
SDK for the QN908x family available for download from:
https://mcuxpresso.nxp.com/en/builder
The files included in these vendor/ directories are released by NXP
under an Open Source license as described in each file, but only the
files used by the next patch are included here.
