powerpc: Move duplicated BAT defines to mmu.h

The BAT fields are architected; there's no need for these to be in
cpu-specific files.  Drop the duplication and move these to
include/asm-ppc/mmu.h.  Also, remove the BL_xxx defines that were only
used by the alaska board, and switch to using the BATU_BL_xxx defines
used by all the other boards.  The BL_ defines previously in use
had to be shifted into the proper position for use, which was inefficient.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
diff --git a/board/etin/kvme080/kvme080.c b/board/etin/kvme080/kvme080.c
index 8c6afc9..21616f5 100644
--- a/board/etin/kvme080/kvme080.c
+++ b/board/etin/kvme080/kvme080.c
@@ -27,6 +27,7 @@
 #include <i2c.h>
 #include <netdev.h>
 #include <asm/processor.h>
+#include <asm/mmu.h>
 
 int checkboard(void)
 {