PCI: dwc: Check CONFIG_PCI_MSI inside dw_pcie_msi_init()

Move the IS_ENABLED(CONFIG_PCI_MSI) check into dw_pcie_msi_init()
instead of duplicating it in all the drivers.

Link: https://lore.kernel.org/r/20200821035420.380495-22-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Richard Zhu <hongxing.zhu@nxp.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Yue Wang <yue.wang@Amlogic.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Xiaowei Song <songxiaowei@hisilicon.com>
Cc: Binghui Wang <wangbinghui@hisilicon.com>
Cc: Stanimir Varbanov <svarbanov@mm-sol.com>
Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: linux-amlogic@lists.infradead.org
Cc: linux-arm-kernel@axis.com
Cc: linux-arm-msm@vger.kernel.org

drivers/pci/controller/dwc/pcie-designware-host.c

@@ -276,6 +276,9 @@ void dw_pcie_msi_init(struct pcie_port *pp)
 	struct device *dev = pci->dev;
 	u64 msi_target;
 
+	if (!IS_ENABLED(CONFIG_PCI_MSI))
+		return;
+
 	pp->msi_page = alloc_page(GFP_KERNEL);
 	pp->msi_data = dma_map_page(dev, pp->msi_page, 0, PAGE_SIZE,
 				    DMA_FROM_DEVICE);