VP8 HWEnc: Modify qp threshold value for mode cost calculatation
VP8 HWEnc: Modify qp threshold value for mode cost calculatation

The patch is helpful to improve quality when qp is lower than the
threshold value.

Signed-off-by: Zhong Li <ad6bffae321e88d39f25028f12e29bb1c91acd98@intel.com>

01org/iotg-lin-gfx-va-driver,uartie/vaapi-intel-driver,uartie/vaapi-intel-driver,chenxianqin/vaapi-intel-driver,chenxianqin/vaapi-intel-driver,uartie/vaapi-intel-driver,uartie/vaapi-intel-driver,01org/iotg-lin-gfx-va-driver,chenxianqin/vaapi-intel-driver,uartie/vaapi-intel-driver,01org/iotg-lin-gfx-va-driver,chenxianqin/vaapi-intel-driver,chenxianqin/vaapi-intel-driver,01org/iotg-lin-gfx-va-driver,01org/iotg-lin-gfx-va-driver