Change hipcc to take HCC_HOME from hipconfig by default

1. Current implementation checks both env var and value in hipconfig and reports error
2. New implementation gives value in hipconfig with highest priority
3. If hipconfig is not present, fall back to env variables.

To Devs: No need to switch between environment variables for different HCC + different HIP.

Change-Id: I6cdf37e1429d7f07be3a68c7e5ba1533d832962b


[ROCm/hip commit: ef68f2f293]

projects/hip/bin/hipcc

@@ -69,10 +69,13 @@ if ($HIP_PLATFORM eq "hcc") {
     $HSA_PATH=$ENV{'HSA_PATH'};
     $HSA_PATH="/opt/rocm/hsa" unless defined $HSA_PATH;
 
-    $HCC_HOME=$ENV{'HCC_HOME'};
-    $HCC_HOME="/opt/rocm/hcc" unless defined $HCC_HOME;
-    $HCC_VERSION=`${HCC_HOME}/bin/hcc --version | cut -d" " -f9 | tr -d "\n"`;
-
+    if($hipConfig{'VALID'} == 0){
+        $HCC_HOME=$ENV{'HCC_HOME'};
+        $HCC_HOME="/opt/rocm/hcc" unless defined $HCC_HOME;
+        $HCC_VERSION=`${HCC_HOME}/bin/hcc --version | cut -d" " -f9 | tr -d "\n"`;
+    }else{
+        $HCC_HOME=$hipConfig{'HCC_HOME'};
+    }
     $ROCM_PATH=$ENV{'ROCM_PATH'};
     $ROCM_PATH="/opt/rocm" unless defined $ROCM_PATH;