SWDEV-322312: RPM packages are generated while build roctracer for UBUNTU

replaced -DCPACK_GENERATOR=DEB

Change-Id: I9f6d4d652e7cad510343731948675f0cd4398ef4

build.sh

@@ -37,7 +37,7 @@ cmake \
     -DCMAKE_PREFIX_PATH="$PREFIX_PATH" \
     -DCMAKE_INSTALL_PREFIX=$PACKAGE_ROOT \
     -DCPACK_PACKAGING_INSTALL_PREFIX=$PACKAGE_PREFIX \
-    -DCPACK_GENERATOR="DEB;RPM" \
+    -DCPACK_GENERATOR="${CPACKGEN:-"DEB;RPM"}" \
     -DCMAKE_SHARED_LINKER_FLAGS="$LD_RUNPATH_FLAG" \
     -DHIP_VDI="$HIP_VDI" \
     -DHIP_API_STRING="$HIP_API_STRING" \