powerpc: Fix bus_space_unmap

Previously it failed to compile since the macro passed too many
arguments to the function.  Fix by adding the bus handle to the
function and adding an implementation that calls pmap_unmapdev.

Reviewed by:	jhibbits
Differential Revision:	https://reviews.freebsd.org/D43440

sys/powerpc/include/bus.h

@@ -103,7 +103,7 @@ struct bus_space {
 	/* mapping/unmapping */
 	int	(*bs_map)(bus_addr_t, bus_size_t, int,
 	    bus_space_handle_t *);
-	void	(*bs_unmap)(bus_size_t);
+	void	(*bs_unmap)(bus_space_handle_t, bus_size_t);
 	int	(*bs_subregion)(bus_space_handle_t, bus_size_t,
 	    bus_size_t, bus_space_handle_t *);
 

sys/powerpc/powerpc/bus_machdep.c

@@ -140,8 +140,13 @@ bs_remap_earlyboot(void)
 }
 
 static void
-bs_gen_unmap(bus_size_t size __unused)
+bs_gen_unmap(bus_space_handle_t bsh, bus_size_t size)
 {
+
+	if (!pmap_bootstrapped)
+		return;
+
+	pmap_unmapdev((void *)bsh, size);
 }
 
 static int