Runtime: fix the incorrect platform info size (conformance).
Runtime: fix the incorrect platform info size (conformance).

As sizeof(str) already includes the '\0', we should not add 1
on the return size. Conformance case computeinfo could pass with
this patch.

(28-Aug 16:51:00)     BEGIN  Compute Info                            :
           ==>  CL_DEVICE_ERROR_CORRECTION_SUPPORT == 0
           ==>  CL_DEVICE_ERROR_CORRECTION_SUPPORT == 0
           ==>  CL_DEVICE_ERROR_CORRECTION_SUPPORT == 0
               PASSED computeinfo.

Signed-off-by: Zhigang Gong <e04a7b9b70b1e4c6318cf117dcd1a9056e14b97a@linux.intel.com>
Reviewed-by: "Yang, Rong R" <78759e37dc7114caed18f74e7515c5cb519dbf6d@intel.com>

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