enhance clGetDeviceInfo() API to return the length of string fields
enhance clGetDeviceInfo() API to return the length of string fields

Signed-off-by: Lu Guanqun <2dad72ae5fe48bf7bd43ddccece96ab3f4a6c25d@intel.com>
Reviewed-by: Zhigang Gong <e04a7b9b70b1e4c6318cf117dcd1a9056e14b97a@linux.intel.com>

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