benet: fix return value check in be_lancer_xmit_workarounds()

in be_lancer_xmit_workarounds(), it should go to label 'tx_drop'
if an unexpected value is returned by pskb_trim().

Fixes: 93040ae5

 ("be2net: Fix to trim skb for padded vlan packets to workaround an ASIC Bug")
Signed-off-by: Yuanjun Gong <ruc_gongyuanjun@163.com>
Link: https://lore.kernel.org/r/20230725032726.15002-1-ruc_gongyuanjun@163.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>