[POWERPC] Add definition of Cell bookmark SPR

Add a definition for the Cell bookmark SPR to asm-powerpc/regs.h.
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>

include/asm-powerpc/reg.h

@@ -553,6 +553,7 @@
 #define SPRN_PA6T_BTCR	978	/* Breakpoint and Tagging Control Register */
 #define SPRN_PA6T_IMAAT	979	/* Instruction Match Array Action Table */
 #define SPRN_PA6T_PCCR	1019	/* Power Counter Control Register */
+#define SPRN_BKMK	1020	/* Cell Bookmark Register */
 #define SPRN_PA6T_RPCCR	1021	/* Retire PC Trace Control Register */