ncsid: Fix if_packet warnings

The new Docker CI now hits the following error.
```
/usr/include/linux/if_packet.h:24:17: error: flexible array member 'sockaddr_ll::<unnamed union>::<unnamed struct>::sll_addr_flex' not at end of 'class ncsi::SockIO'
   24 |                 __DECLARE_FLEX_ARRAY(unsigned char, sll_addr_flex);
      |                 ^~~~~~~~~~~~~~~~~~~~
../subprojects/ncsid/src/ncsi_sockio.h:55:15: note: next member 'const int ncsi::SockIO::kpoll_timeout_' declared here
   55 |     const int kpoll_timeout_ = 10;
      |               ^~~~~~~~~~~~~~
../subprojects/ncsid/src/ncsi_sockio.h:29:7: note: in the definition of 'class ncsi::SockIO'
   29 | class SockIO : public net::SockIO
```

Removed the sockaddr_ll variable.

Change-Id: I67e700f6cd728bfbc822c1b8661915f8306711a1
Signed-off-by: Willy Tu <wltu@google.com>
diff --git a/subprojects/ncsid/test/net_iface_mock.cpp b/subprojects/ncsid/test/net_iface_mock.cpp
index 5e2d223..88d3177 100644
--- a/subprojects/ncsid/test/net_iface_mock.cpp
+++ b/subprojects/ncsid/test/net_iface_mock.cpp
@@ -20,7 +20,7 @@
 namespace mock
 {
 
-int IFace::bind_sock(int sockfd, struct sockaddr_ll*) const
+int IFace::bind_sock(int sockfd) const
 {
     bound_socks.push_back(sockfd);
     return 0;
diff --git a/subprojects/ncsid/test/net_iface_mock.h b/subprojects/ncsid/test/net_iface_mock.h
index 118ca03..a8a5be1 100644
--- a/subprojects/ncsid/test/net_iface_mock.h
+++ b/subprojects/ncsid/test/net_iface_mock.h
@@ -29,7 +29,7 @@
   public:
     IFace() : net::IFaceBase("mock0") {}
     explicit IFace(const std::string& name) : net::IFaceBase(name) {}
-    int bind_sock(int sockfd, struct sockaddr_ll* saddr) const override;
+    int bind_sock(int sockfd) const override;
 
     mutable std::vector<int> bound_socks;
     int index;