ARM: mvebu: Fix coherency bus notifiers by using separate notifiers

Currently, the coherency fabric support registers two bus notifiers;
one for platform, one for pci bus types, with the same notifier block.
However, this is illegal and can cause serious issues: the notifier
block is also a link in the notifier list and cannot be inserted twice.

This commit fixes this by using different notifier blocks (with the same
notifier callback) to set the platform and pci bus types notifiers.

Fixes: b0063aad ("ARM: mvebu: use hardware I/O coherency also for PCI devices")
Reported-by: NPaolo Pisati <p.pisati@gmail.com>
Signed-off-by: NEzequiel Garcia <ezequiel.garcia@free-electrons.com>
Link: https://lkml.kernel.org/r/1404826657-6977-1-git-send-email-ezequiel.garcia@free-electrons.comSigned-off-by: NJason Cooper <jason@lakedaemon.net>

arch/arm/mach-mvebu/coherency.c

@@ -292,6 +292,10 @@ static struct notifier_block mvebu_hwcc_nb = {
 	.notifier_call = mvebu_hwcc_notifier,
 };
 
+static struct notifier_block mvebu_hwcc_pci_nb = {
+	.notifier_call = mvebu_hwcc_notifier,
+};
+
 static void __init armada_370_coherency_init(struct device_node *np)
 {
 	struct resource res;
@@ -427,7 +431,7 @@ static int __init coherency_pci_init(void)
 {
 	if (coherency_available())
 		bus_register_notifier(&pci_bus_type,
-				       &mvebu_hwcc_nb);
+				       &mvebu_hwcc_pci_nb);
 	return 0;
 }