Add another EPB checks for preventing out-of-bound operation

[7erryX]

OSV-2023-159

isvce_cabac_flush(isvce_cabac_ctxt_t *ps_cabac_ctxt) in encoder/svc/isvce_cabac.c once caused OSV-2023-159 and was fixed in Commit ab835f3
by adding extra EPB check

Similar Code Snippet

The following code contains a similar logic

libavc/encoder/ih264e_cabac.c

Line 403 in 4064713

if (pu1_strm_buf[ps_stream->u4_strm_buf_offset - 1] == 0x03

Would it make sense to fix it in the same way?