ppp: make ppp_lcp.h self-contained

We need to include "ppp.h" to define 'struct ppp_layer_data_t' and
'struct ppp_handler_t'.
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>

accel-pppd/ppp/ppp_lcp.h

@@ -4,7 +4,9 @@
 #include <stdint.h>
 
 #include "triton.h"
+#include "ppp.h"
 #include "ppp_fsm.h"
+
 /*
  * Options.
  */