change Mseal signature to accept a []byte as first argument

Author: mauri870

unix/syscall_linux.go

@@ -2592,4 +2592,4 @@ func SchedGetAttr(pid int, flags uint) (*SchedAttr, error) {
 }
 
 //sys	Cachestat(fd uint, crange *CachestatRange, cstat *Cachestat_t, flags uint) (err error)
-//sys	Mseal(addr uintptr, len int, flags uint) (err error)
+//sys	Mseal(b []byte, flags uint) (err error)