Migrate CAN bus HAL to nested namespaces

Test: it builds
Change-Id: I83d9ef4f1fff1585e6487c95f09b55b1aa5b3e63
diff --git a/automotive/can/1.0/default/CanBusSlcan.cpp b/automotive/can/1.0/default/CanBusSlcan.cpp
index 7dce838..29d9d3c 100644
--- a/automotive/can/1.0/default/CanBusSlcan.cpp
+++ b/automotive/can/1.0/default/CanBusSlcan.cpp
@@ -25,12 +25,7 @@
 #include <sys/stat.h>
 #include <termios.h>
 
-namespace android {
-namespace hardware {
-namespace automotive {
-namespace can {
-namespace V1_0 {
-namespace implementation {
+namespace android::hardware::automotive::can::V1_0::implementation {
 
 namespace slcanprotocol {
 static const std::string kOpenCommand = "O\r";
@@ -158,9 +153,4 @@
     return true;
 }
 
-}  // namespace implementation
-}  // namespace V1_0
-}  // namespace can
-}  // namespace automotive
-}  // namespace hardware
-}  // namespace android
+}  // namespace android::hardware::automotive::can::V1_0::implementation