fix vp8 decode issue intel#190, change the first partition size

when the count in VABoolCoderContextVPX is zero, actually it means there are 8 bit in bool coder

correct first partition_size,when there is 8 bits in bool coder

Signed-off-by: XinfengZhang <carl.zhang@intel.com>

media_driver/linux/common/codec/ddi/media_ddi_decode_vp8.cpp

@@ -84,12 +84,17 @@ VAStatus DdiDecodeVP8::ParseSliceParams(
     picParams->CodedCoeffTokenPartition = (num_token_partitions != 8) ? (num_token_partitions >> 1) : 3;
     //macroblock_offset is in unit of bit.it should be always the next byte, the byte is divided to two parts
     //used bits and remaining bits, if used bits == 8, uiFirstMbByteOffset should add 1, so use 8 to do the ceil operator
-    picParams->uiFirstMbByteOffset = slcParam->slice_data_offset + ((slcParam->macroblock_offset + 8) >> 3);
+    picParams->uiFirstMbByteOffset = slcParam->slice_data_offset + ((slcParam->macroblock_offset + 7) >> 3);
 
     memcpy_s(picParams->uiPartitionSize, sizeof(picParams->uiPartitionSize), slcParam->partition_size, sizeof(picParams->uiPartitionSize));
 
     //partition 0 size in command buffer includes the one byte in bool decoder if remaining bits of bool decoder is not zero.
-    picParams->uiPartitionSize[0] += (slcParam->macroblock_offset & 0x7) ? 1 : 0;
+    //bool coder count should be 0-7, if it is 0 (ucP0EntropyCount == 0), actually it means there are 8 bit is loaded in bool coder.
+    if(picParams->ucP0EntropyCount == 0)
+    {
+        picParams->uiFirstMbByteOffset += 1;
+        picParams->uiPartitionSize[0] -= 1;
+    }
 
     return VA_STATUS_SUCCESS;
 }