powerpc: Add the DAWR support to the set_break()

This adds DAWR supoprt to the set_break().

It does both bare metal and PAPR versions of setting the DAWR.

There is still some work we can do to make full use of the watchpoint but that
will come later.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/machdep.h

@@ -180,6 +180,10 @@ struct machdep_calls {
 	int		(*set_dabr)(unsigned long dabr,
 				    unsigned long dabrx);
 
+	/* Set DAWR for this platform, leave empty for default implemenation */
+	int		(*set_dawr)(unsigned long dawr,
+				    unsigned long dawrx);
+
 #ifdef CONFIG_PPC32	/* XXX for now */
 	/* A general init function, called by ppc_init in init/main.c.
 	   May be NULL. */