The `broadmobi`, `dlink`, `telit` and `tplink` plugins include the
`mm-port-enums-types.h` header. However, they do not use any symbol
defined there.
The `huawei` plugin as includes the `mm-port-enums-types.h` header
but it does not include the build targets as dependencies.
These issues have been fixed by removing the unnecessary includes
from `broadmobi`, `dlink`, `telit` and `tplink` plugins and by
including the enums build target in the `huawei` target.