Audio V4: Update namespace and version of 4.0 shim

Put the shim in a V4_0 namespace to comply with the ODR.
Make the include guard unique.
Split from the error prone interface adaptation change for safer review.

Patch generated with:
sed -i 's/V2_0/V4_0/g' *
sed -i "/include.*2.0/s/2\.0/4.0/" *
sed -i '/namespace android *{/anamespace V4_0 {' *
sed -Ei 's/(ifndef|define|endif)(.*)_H/\1\2_4_0_H/' *
sed -Ei 's#}(.*)namespace android$#}\1namespace V4_0\n\0#' *

Bug: 38184704
Test: Compile
Change-Id: I7d3aa46b3dfec664cbeea8a6b946456b8e8f06e3
Signed-off-by: Kevin Rocard <krocard@google.com>
diff --git a/media/libaudiohal/4.0/DevicesFactoryHalHybrid.cpp b/media/libaudiohal/4.0/DevicesFactoryHalHybrid.cpp
index 77df6b5..722b95a 100644
--- a/media/libaudiohal/4.0/DevicesFactoryHalHybrid.cpp
+++ b/media/libaudiohal/4.0/DevicesFactoryHalHybrid.cpp
@@ -22,6 +22,7 @@
 #include "DevicesFactoryHalHidl.h"
 
 namespace android {
+namespace V4_0 {
 
 DevicesFactoryHalHybrid::DevicesFactoryHalHybrid()
         : mLocalFactory(new DevicesFactoryHalLocal()),
@@ -38,4 +39,5 @@
     return mLocalFactory->openDevice(name, device);
 }
 
+} // namespace V4_0
 } // namespace android