PCI: pci-dra7xx: Prepare for deferred probe with module_platform_driver

After updating pci-dra7xx driver to probe with ti-sysc and genpd, I
noticed that dra7xx_pcie_probe() would not run if a power-domains property
was configured for the interconnect target module.

Turns out that module_platform_driver_probe uses platform_driver_probe(),
while builtin_platform_driver uses platform_driver_register().

Only platform_driver_register() works for deferred probe as noted in the
comments for __platform_driver_probe() in drivers/base/platform.c with a
line saying "Note that this is incompatible with deferred probing".

With module_platform_driver_probe, we have platform_driver_probe() produce
-ENODEV error at device_initcall() level, and no further attempts are done.
Let's fix this by using module_platform_driver instead.

Note this is not an issue currently as we probe devices with simple-bus,
and only is needed as we start probing the device with ti-sysc, or when
probed with simple-pm-bus.

Note that we must now also remove __init for probe related functions to
avoid a section mismatch warning.

Cc: linux-pci@vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

drivers/pci/controller/dwc/pci-dra7xx.c

@@ -443,8 +443,8 @@ static const struct dw_pcie_ep_ops pcie_ep_ops = {
 	.get_features = dra7xx_pcie_get_features,
 };
 
-static int __init dra7xx_add_pcie_ep(struct dra7xx_pcie *dra7xx,
-				     struct platform_device *pdev)
+static int dra7xx_add_pcie_ep(struct dra7xx_pcie *dra7xx,
+			      struct platform_device *pdev)
 {
 	int ret;
 	struct dw_pcie_ep *ep;
@@ -472,8 +472,8 @@ static int __init dra7xx_add_pcie_ep(struct dra7xx_pcie *dra7xx,
 	return 0;
 }
 
-static int __init dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx,
-				       struct platform_device *pdev)
+static int dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx,
+				struct platform_device *pdev)
 {
 	int ret;
 	struct dw_pcie *pci = dra7xx->pci;
@@ -682,7 +682,7 @@ static int dra7xx_pcie_configure_two_lane(struct device *dev,
 	return 0;
 }
 
-static int __init dra7xx_pcie_probe(struct platform_device *pdev)
+static int dra7xx_pcie_probe(struct platform_device *pdev)
 {
 	u32 reg;
 	int ret;
@@ -938,6 +938,7 @@ static const struct dev_pm_ops dra7xx_pcie_pm_ops = {
 };
 
 static struct platform_driver dra7xx_pcie_driver = {
+	.probe = dra7xx_pcie_probe,
 	.driver = {
 		.name	= "dra7-pcie",
 		.of_match_table = of_dra7xx_pcie_match,
@@ -946,4 +947,4 @@ static struct platform_driver dra7xx_pcie_driver = {
 	},
 	.shutdown = dra7xx_pcie_shutdown,
 };
-builtin_platform_driver_probe(dra7xx_pcie_driver, dra7xx_pcie_probe);
+builtin_platform_driver(dra7xx_pcie_driver);