Add delay after trigerring DIMM VPD Collection

Since systems can have a number of DIMMs (as opposed to other FRUs) and
the DIMM VPD collection is only kicked off after the primary processor
VPD is collected, add a small delay at the end of trigerring the udev
events for all DIMMs.

This ensures that we can properly wait for all the VPD to be collected
before we can reach BMC Ready state.

Signed-off-by: Santosh Puranik <santosh.puranik@in.ibm.com>
Change-Id: I96ebee1cb9ecddd35ba590faf1cfcb05ce0378b0
diff --git a/ibm_vpd_app.cpp b/ibm_vpd_app.cpp
index 43241bc..fbbdc92 100644
--- a/ibm_vpd_app.cpp
+++ b/ibm_vpd_app.cpp
@@ -25,6 +25,7 @@
 #include <nlohmann/json.hpp>
 #include <phosphor-logging/log.hpp>
 #include <regex>
+#include <thread>
 
 using namespace std;
 using namespace openpower::vpd;
@@ -1090,6 +1091,9 @@
                 if (chipVersion >= 2)
                 {
                     doEnableAllDimms(js);
+                    // Sleep for a few seconds to let the DIMM parses start
+                    using namespace std::chrono_literals;
+                    std::this_thread::sleep_for(5s);
                 }
             }
         }