Fix google-build-using-namespace warnings in rs.

* Most files define classes in renderscript namespace.
  Define them in the namespace instead of "using namespace ...".
  Some files define global C++ names, and we replace
  "using namespace ..." with using declarations of the required names.
* Add "NOLINT" comment to rsg_generator.c output code to suppress
  such warnings.

Bug: 32670901
Test: build with WITH_TIDY=1
Change-Id: I9b0edcad3e1fb37c79927b05fd58fb1a301bdf22
diff --git a/rsMutex.cpp b/rsMutex.cpp
index 557c588..40671d5 100644
--- a/rsMutex.cpp
+++ b/rsMutex.cpp
@@ -16,9 +16,8 @@
 
 #include "rsMutex.h"
 
-using namespace android;
-using namespace android::renderscript;
-
+namespace android {
+namespace renderscript {
 
 Mutex::Mutex() {
 }
@@ -56,4 +55,5 @@
     return true;
 }
 
-
+} // namespace renderscript
+} // namespace android