lapd_pcap.h: Add missing #include lines

we reference 'struct msgb' and mode_t, so we have to #include
the right header files.

Change-Id: Iac8f905182b60782202bdf75e04d47ea89dc3863
diff --git a/include/osmocom/abis/lapd_pcap.h b/include/osmocom/abis/lapd_pcap.h
index e1b587e..36ddd7f 100644
--- a/include/osmocom/abis/lapd_pcap.h
+++ b/include/osmocom/abis/lapd_pcap.h
@@ -1,6 +1,9 @@
 #ifndef _LAPD_PCAP_H_
 #define _LAPD_PCAP_H_
 
+#include <sys/types.h>
+#include <osmocom/core/msgb.h>
+
 #define OSMO_LAPD_PCAP_INPUT	0
 #define OSMO_LAPD_PCAP_OUTPUT	1