[PowerPC64LE] Bus space prep for LE

Swap the BE and LE bus_space tags when on LE, and adjust the nexus tag
to match.

This is prep for a a followup that makes the powerpc bus_space macros easier
to maintain in the future.

Sponsored by:	Tag1 Consulting, Inc.

sys/powerpc/powerpc/bus_machdep.c

@@ -790,7 +790,11 @@ bs_le_sr_8(bus_space_handle_t bsh, bus_size_t ofs, uint64_t val, size_t cnt)
 	TODO;
 }
 
+#if BYTE_ORDER == LITTLE_ENDIAN
+struct bus_space bs_le_tag = {
+#else
 struct bus_space bs_be_tag = {
+#endif
 	/* mapping/unmapping */
 	bs_gen_map,
 	bs_gen_unmap,
@@ -884,7 +888,11 @@ struct bus_space bs_be_tag = {
 	bs_be_sr_8,
 };
 
+#if BYTE_ORDER == LITTLE_ENDIAN
+struct bus_space bs_be_tag = {
+#else
 struct bus_space bs_le_tag = {
+#endif
 	/* mapping/unmapping */
 	bs_gen_map,
 	bs_gen_unmap,

sys/powerpc/powerpc/nexus.c

@@ -35,6 +35,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <sys/endian.h>
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bus.h>
@@ -173,7 +174,11 @@ static bus_space_tag_t
 nexus_get_bus_tag(device_t bus __unused, device_t child __unused)
 {
 
+#if BYTE_ORDER == LITTLE_ENDIAN
+	return(&bs_le_tag);
+#else
 	return(&bs_be_tag);
+#endif
 }
 
 static int