VP8 HWEnc: Alloc larger memory for internal buffer
VP8 HWEnc: Alloc larger memory for internal buffer

It is to prevent the internal bitstream buffer overflow when qp is low.

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

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