mapper: use async client for GetSubTreePaths

Use the generated client bindings instead of hard-coding strings for
function names and parameters.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ica2c6f29961a81a484548a8f74634067c53cec3d
diff --git a/health_utils.hpp b/health_utils.hpp
index ded0159..7a924e5 100644
--- a/health_utils.hpp
+++ b/health_utils.hpp
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <sdbusplus/async.hpp>
 #include <sdbusplus/bus.hpp>
 #include <sdbusplus/sdbus.hpp>
 
@@ -13,6 +14,7 @@
 /** @brief Start a systemd unit */
 void startUnit(sdbusplus::bus_t& bus, const std::string& sysdUnit);
 /** @brief Find D-Bus paths for given interface */
-auto findPaths(sdbusplus::bus_t& bus, const std::string& iface) -> paths_t;
+auto findPaths(sdbusplus::async::context& ctx, const std::string& iface,
+               const std::string& subpath) -> sdbusplus::async::task<paths_t>;
 
 } // namespace phosphor::health::utils