Migrate CAN bus HAL to nested namespaces

Test: it builds
Change-Id: I83d9ef4f1fff1585e6487c95f09b55b1aa5b3e63
diff --git a/automotive/can/1.0/default/libnetdevice/common.h b/automotive/can/1.0/default/libnetdevice/common.h
index 9bdff4d..8097f37 100644
--- a/automotive/can/1.0/default/libnetdevice/common.h
+++ b/automotive/can/1.0/default/libnetdevice/common.h
@@ -18,8 +18,7 @@
 
 #include <string>
 
-namespace android {
-namespace netdevice {
+namespace android::netdevice {
 
 /**
  * Returns the index of a given network interface.
@@ -32,5 +31,4 @@
  */
 unsigned int nametoindex(const std::string& ifname);
 
-}  // namespace netdevice
-}  // namespace android
+}  // namespace android::netdevice