benchdnn: doc: add newly add f8_e4m3 and f8_e5m2

tests/benchdnn/doc/knobs_dt.md

@@ -10,6 +10,8 @@ The following data types are supported:
 | s32       | standard int or int32_t
 | s8        | standard char or int8_t
 | u8        | standard unsigned char or uint8_t
+| f8_e4m3   | 1-byte float (1 sign bit, 4 exp bits, 3 mantissa bits)
+| f8_e5m2   | 1-byte float (1 sign bit, 5 exp bits, 2 mantissa bits)
 | f16       | 2-byte float (1 sign bit, 5 exp bits, 10 mantissa bits)
 | bf16      | 2-byte float (1 sign bit, 8 exp bits, 7 mantissa bits)
 | f64       | double precision float