PCI: aardvark: Fix return value of MSI domain .alloc() method

commit e4313be1599d397625c14fb7826996813622decf upstream.

MSI domain callback .alloc() (implemented by advk_msi_irq_domain_alloc()
function) should return zero on success, since non-zero value indicates
failure.

When the driver was converted to generic MSI API in commit f21a8b1b6837
("PCI: aardvark: Move to MSI handling using generic MSI support"), it
was converted so that it returns hwirq number.

Fix this.

Link: https://lore.kernel.org/r/20211028185659.20329-3-kabel@kernel.org
Fixes: f21a8b1b6837 ("PCI: aardvark: Move to MSI handling using generic MSI support")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/pci/host/pci-aardvark.c b/drivers/pci/host/pci-aardvark.c
index 43f0e20..ce137e4 100644
--- a/drivers/pci/host/pci-aardvark.c
+++ b/drivers/pci/host/pci-aardvark.c
@@ -662,7 +662,7 @@
 				    domain->host_data, handle_simple_irq,
 				    NULL, NULL);
 
-	return hwirq;
+	return 0;
 }
 
 static void advk_msi_irq_domain_free(struct irq_domain *domain,