change project language to HIP; identify tests as cmake subdir

Signed-off-by: Karl W Schulz <karl.schulz@amd.com>

CMakeLists.txt

@@ -27,10 +27,12 @@ string(REGEX REPLACE "([0-9]+)\.([0-9]+)\.([0-9]+)(.*)" "\\1.\\2.\\3" OMNIPERF_V
 project(
     omniperf
     VERSION ${OMNIPERF_VERSION}
-    LANGUAGES C
+    LANGUAGES HIP
     DESCRIPTION "OmniPerf"
     HOMEPAGE_URL "https://github.com/ROCm/omniperf")
 
+set(CMAKE_HIP_FLAGS_RELEASE "-O2")
+
 include(ExternalProject)
 include(GNUInstallDirs)
 
@@ -156,6 +158,8 @@ if(${GIT_CLONE})
 endif()
 
 # Setup testing collateral
+add_subdirectory(tests)
+
 enable_testing()
 
 option(ENABLE_COVERAGE "Enable code coverage" OFF)