PCI: apple: Dynamically allocate RID-to_SID bitmap

As we move towards supporting SoCs with varying RID-to-SID mapping
capabilities, turn the static SID tracking bitmap into a dynamically
allocated one. The current allocation size is still the same, but
that's about to change.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Link: https://patch.msgid.link/20250401091713.2765724-7-maz@kernel.org

Author: Marc Zyngier

drivers/pci/controller/pcie-apple.c

@@ -147,7 +147,7 @@ struct apple_pcie_port {
 	void __iomem		*base;
 	struct irq_domain	*domain;
 	struct list_head	entry;
-	DECLARE_BITMAP(sid_map, MAX_RID2SID);
+	unsigned long		*sid_map;
 	int			sid_map_sz;
 	int			idx;
 };
@@ -524,6 +524,10 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
 	if (!port)
 		return -ENOMEM;
 
+	port->sid_map = devm_bitmap_zalloc(pcie->dev, MAX_RID2SID, GFP_KERNEL);
+	if (!port->sid_map)
+		return -ENOMEM;
+
 	ret = of_property_read_u32_index(np, "reg", 0, &idx);
 	if (ret)
 		return ret;