i40evf/i40evf_main: Fix variable assignment in i40evf_parse_cls_flower

It seems this is a copy-paste error and that the proper variable to use
in this particular case is _src_ instead of _dst_.

Addresses-Coverity-ID: 1465282 ("Copy-paste error")
Fixes: 0075fa0f ("i40evf: Add support to apply cloud filters")
Signed-off-by: Gustavo A R Silva <garsilva@embeddedor.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>