`libjail/jail.c' includes both <sys/param.h> and <sys/types.h>

Latter is undesired when including <sys/param.h> according to style(9)

Submitted by:	Faraz Vahedi
Reviewed by:	cem
Differential Revision:	https://reviews.freebsd.org/D20637

lib/libjail/jail.c

@@ -30,7 +30,6 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
-#include <sys/types.h>
 #include <sys/jail.h>
 #include <sys/linker.h>
 #include <sys/socket.h>