bnxt_en: Fix coredump logic to free allocated buffer

When handling HWRM_DBG_COREDUMP_LIST FW command in
bnxt_hwrm_dbg_dma_data(), the allocated buffer info->dest_buf is
not freed in the error path.  In the normal path, info->dest_buf
is assigned to coredump->data and it will eventually be freed after
the coredump is collected.

Free info->dest_buf immediately inside bnxt_hwrm_dbg_dma_data() in
the error path.

Fixes: c74751f4 ("bnxt_en: Return error if FW returns more data than dump length")
Reported-by: Michael Chan <michael.chan@broadcom.com>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Shruti Parab <shruti.parab@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>