powerpc: Update xmon to use ppc_breakpoint_available()

The 'bd' command will now print an error and not set the breakpoint on
P9.
Signed-off-by: Michael Neuling <mikey@neuling.org>
[mpe: Unsplit quoted string]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/xmon/xmon.c

@@ -1297,6 +1297,10 @@ bpt_cmds(void)
 	static const char badaddr[] = "Only kernel addresses are permitted for breakpoints\n";
 	int mode;
 	case 'd':	/* bd - hardware data breakpoint */
+		if (!ppc_breakpoint_available()) {
+			printf("Hardware data breakpoint not supported on this cpu\n");
+			break;
+		}
 		mode = 7;
 		cmd = inchar();
 		if (cmd == 'r')