Add generated header and PCH to gitignore
Add generated header and PCH to gitignore

Signed-off-by: Simon Richter <a81c4837b87e3f24f0a93a4e7a4570dd57cfdbfd@hogyros.de>
Reviewed-by: He Junyan <8f73a735c668918c9613b750d3a88ebf2489599f@inbox.com>
Reviewed-by: Zhigang Gong <e04a7b9b70b1e4c6318cf117dcd1a9056e14b97a@linux.intel.com>

ignatenkobrain/beignet,zhenyw/beignet,ignatenkobrain/beignet,wdv4758h/beignet,freedesktop-unofficial-mirror/beignet,ignatenkobrain/beignet,wdv4758h/beignet,zhenyw/beignet,freedesktop-unofficial-mirror/beignet,wdv4758h/beignet,zhenyw/beignet,freedesktop-unofficial-mirror/beignet,ignatenkobrain/beignet,wdv4758h/beignet,ignatenkobrain/beignet,zhenyw/beignet,zhenyw/beignet,freedesktop-unofficial-mirror/beignet,wdv4758h/beignet