[GPU Service] Name GPU service back to "gpu"

Changed the GPU service name back to be compatible with external
engines/tools' usage of vkjson cmd.

Bug: 118347356
Test: adb shell cmd gpu vkjson
Change-Id: I8830149e6f239d95a7397329ba2f8bc99561d494
diff --git a/services/gpuservice/GpuService.cpp b/services/gpuservice/GpuService.cpp
index e4ca6bc..150896c 100644
--- a/services/gpuservice/GpuService.cpp
+++ b/services/gpuservice/GpuService.cpp
@@ -62,7 +62,7 @@
     status_t cmd_vkjson(int out, int err);
 }
 
-const char* const GpuService::SERVICE_NAME = "gpuservice";
+const char* const GpuService::SERVICE_NAME = "gpu";
 
 GpuService::GpuService() = default;