GBE: improve precision of exp10
GBE: improve precision of exp10

Signed-off-by: Lv Meng <2df664ee4255226675c7b29e26307ac8da3842dc@intel.com>
Tested-by: Zhigang Gong <e04a7b9b70b1e4c6318cf117dcd1a9056e14b97a@linux.intel.com>

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