Currently burst is clamping on rate and not burst, the assignment
of burst from the clamping discards the previous assignment of burst.
This looks like a cut-n-paste error from the previous clamping
calculation on ramp.  Fix this by replacing ramp with burst.

Addresses-Coverity: ("Unused value")
Fixes: 0fbabf87 ("net: dsa: felix: add support Credit Based Shaper(CBS) for hardware offload")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>