powerpc/xive: use true and false for bool variable

fixed the following coccicheck:
./arch/powerpc/sysdev/xive/spapr.c:552:8-9: WARNING: return of 0/1 in
function 'xive_spapr_match' with return type bool
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1615793096-83758-1-git-send-email-yang.lee@linux.alibaba.com

arch/powerpc/sysdev/xive/spapr.c

@@ -549,7 +549,7 @@ static void xive_spapr_cleanup_queue(unsigned int cpu, struct xive_cpu *xc,
 static bool xive_spapr_match(struct device_node *node)
 {
 	/* Ignore cascaded controllers for the moment */
-	return 1;
+	return true;
 }
 
 #ifdef CONFIG_SMP