libclat: Remove redundant "using android::net::.*"

They are already under the same namespace.

Test: presubmit
Bug: 219872355
Change-Id: I5f51cf2c38755c99f220870c2ffe66ee8c454514
diff --git a/service/native/libs/libclat/bpfhelper.cpp b/service/native/libs/libclat/bpfhelper.cpp
index 6e230d0..00785ad 100644
--- a/service/native/libs/libclat/bpfhelper.cpp
+++ b/service/native/libs/libclat/bpfhelper.cpp
@@ -28,16 +28,6 @@
 #define DEVICEPREFIX "v4-"
 
 using android::base::unique_fd;
-using android::net::RAWIP;
-using android::net::getClatEgress4MapFd;
-using android::net::getClatIngress6MapFd;
-using android::net::getClatEgress4ProgFd;
-using android::net::getClatIngress6ProgFd;
-using android::net::tcQdiscAddDevClsact;
-using android::net::tcFilterAddDevEgressClatIpv4;
-using android::net::tcFilterAddDevIngressClatIpv6;
-using android::net::tcFilterDelDevEgressClatIpv4;
-using android::net::tcFilterDelDevIngressClatIpv6;
 using android::bpf::BpfMap;
 
 BpfMap<ClatEgress4Key, ClatEgress4Value> mClatEgress4Map;