bnxt_en: Add separate function to delete the filter structure

bnxt_en: Add separate function to delete the filter structure

Since we are going to do filter deletion at multiple places in the
upcoming patches, add a function that does the deletion.  Future patches
add more code into this function.

Since we are passing the address of the filter base to free the
entire filter structure, add a comment to make sure that the base
is always at the beginning of the structure.

Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20240205223202.25341-8-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>