Fixed out of bound read in flush_bits

Bug: 28168413
Change-Id: I3db5432a08daf665e160c0dab2d1928a576418b4

INLINE UWORD32 impeg2d_bit_stream_get(void* pv_ctxt, UWORD32 u4_num_bits)
{
    UWORD32 u4_next_bits = impeg2d_bit_stream_nxt(pv_ctxt, u4_num_bits);
    impeg2d_bit_stream_flush(pv_ctxt, u4_num_bits);
 return(u4_next_bits);
}

INLINE UWORD32 impeg2d_bit_stream_get(void* pv_ctxt, UWORD32 u4_num_bits)
{
    UWORD32 u4_next_bits = impeg2d_bit_stream_nxt(pv_ctxt, u4_num_bits);
    impeg2d_bit_stream_flush(pv_ctxt, u4_num_bits);
 return(u4_next_bits);
}
