Migrate CAN bus HAL to nested namespaces

Test: it builds
Change-Id: I83d9ef4f1fff1585e6487c95f09b55b1aa5b3e63
diff --git a/automotive/can/1.0/default/libnetdevice/common.cpp b/automotive/can/1.0/default/libnetdevice/common.cpp
index 3deac3e..5c62443 100644
--- a/automotive/can/1.0/default/libnetdevice/common.cpp
+++ b/automotive/can/1.0/default/libnetdevice/common.cpp
@@ -20,8 +20,7 @@
 
 #include <net/if.h>
 
-namespace android {
-namespace netdevice {
+namespace android::netdevice {
 
 unsigned int nametoindex(const std::string& ifname) {
     const auto ifidx = if_nametoindex(ifname.c_str());
@@ -34,5 +33,4 @@
     return 0;
 }
 
-}  // namespace netdevice
-}  // namespace android
+}  // namespace android::netdevice