transport: Update internal header file

Rename the header guard to be in-line with other internal headers and
less likely to conflict with other headers. Also remove the c++ guard as
we don't need it in an internal header.

Signed-off-by: Rashmica Gupta <rashmica@linux.ibm.com>
Change-Id: I86ef4d478fca62a5532fbc440216e0898a463821
diff --git a/src/transport/transport.h b/src/transport/transport.h
index 28d7f9b..0353b25 100644
--- a/src/transport/transport.h
+++ b/src/transport/transport.h
@@ -1,9 +1,5 @@
-#ifndef TRANSPORT_H
-#define TRANSPORT_H
-
-#ifdef __cplusplus
-extern "C" {
-#endif
+#ifndef LIBPLDM_SRC_TRANSPORT_TRANSPORT_H
+#define LIBPLDM_SRC_TRANSPORT_TRANSPORT_H
 
 #include "libpldm/base.h"
 #include "libpldm/requester/pldm.h"
@@ -31,8 +27,4 @@
 			   struct pollfd *pollfd);
 };
 
-#ifdef __cplusplus
-}
-#endif
-
-#endif // TRANSPORT_H
+#endif // LIBPLDM_SRC_TRANSPORT_TRANSPORT_H