bgpd: clear misleading mismatched check

bgpd: clear misleading mismatched check

Two changes for `delete_global_type2_routes()`:

1) Remove check of `bgp_dest_has_bgp_path_info_data(rddest)`.
It is unnecessary(`dest->info` should not be NULL) and misleading.
`if (rddest && bgp_dest_has_bgp_path_info_data(rddest))`
Use (locked) node with this check, but unlock with `if (rddest)`,
The mismatched condition is misleading, there seems to be a
mistake to extra unlock.
Just make it clear, immediately exit with `(!rddest)`.

2) Remove checking returned value for it, and use `void` as return type.
It is unnecessary and wrong. Even the check failed, it should continue
to delete other types of routes.
Just remove the check and go through.

Signed-off-by: anlan_cs <vic.lan@pica8.com>