libpldm: Migrate to subproject

Organize files in libpldm to make it a subproject

In the current state, libpldm is not readily consumable
as a subproject.This commit does all the necessary re-organisation
of the source code to make it work as a subproject.

There are no .c/.h files changes in this commit, only meson
changes and re-organising the code structure.

Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>
Change-Id: I20a71c0c972b1fd81fb359d604433618799102c6
diff --git a/src/oem/ibm/meson.build b/src/oem/ibm/meson.build
new file mode 100644
index 0000000..04bb24f
--- /dev/null
+++ b/src/oem/ibm/meson.build
@@ -0,0 +1,5 @@
+libpldm_sources += files(
+  'file_io.c',
+  'host.c',
+  'platform.c'
+  )