libpldm : Add encode API for QueryDeviceIdentifiers cmd

QueryDeviceIdentifiers command is used by update agent to obtain the
firmware identifiers for the fimrware device and its defined in DSP0267
Version 1.1.0 sec:10.1.

Tested: Unit tests passed

Signed-off-by: gokulsanker <gokul.sanker.v.g@intel.com>
Change-Id: I472e85414b1a04b550b88c3e6058b86efb9b89b1
diff --git a/libpldm/meson.build b/libpldm/meson.build
index e884f66..0d868f9 100644
--- a/libpldm/meson.build
+++ b/libpldm/meson.build
@@ -9,7 +9,8 @@
   'state_set.h',
   'fru.h',
   'utils.h',
-  'pdr.h'
+  'pdr.h',
+  'firmware_update.h'
 ]
 
 sources = [
@@ -19,7 +20,8 @@
   'bios_table.c',
   'fru.c',
   'utils.c',
-  'pdr.c'
+  'pdr.c',
+  'firmware_update.c'
 ]
 
 libpldm_headers = ['.', '..']