cpucontrol: print more useful information when MSR access fails.

Instead of providing ioctl cmd value, which has no meaning to user,
print MSR number.  The later is what the user expects in this place
even.

Reported by:	pstef
Sponsored by:	The FreeBSD Foundation
MFC after:	3 days

usr.sbin/cpucontrol/cpucontrol.c

@@ -307,7 +307,7 @@ do_msr(const char *cmdarg, const char *dev)
 	}
 	error = ioctl(fd, command, &args);
 	if (error < 0) {
-		WARN(0, "ioctl(%s, CPUCTL_%s (%lu))", dev, command_name, command);
+		WARN(0, "ioctl(%s, CPUCTL_%s (%#x))", dev, command_name, msr);
 		close(fd);
 		return (1);
 	}