fix(linux): Add PCIe resource reallocation note for VF enumeration

Add a note to the PCIe Root Complex documentation about using 'pci=realloc'
bootargs parameter when the root complex is connected to an endpoint with
Virtual Functions and kernel panics during enumeration. This parameter
instructs the Linux kernel to reallocate PCI bridge resources, helping
to resolve conflicts during PCIe device enumeration.

Signed-off-by: Aksh Garg <a-garg7@ti.com>

Author: AkshGarg-19

source/linux/Foundational_Components/Kernel/Kernel_Drivers/PCIe/PCIe_Root_Complex.rst

@@ -197,6 +197,20 @@ Following is a brief explanation of layers shown in the diagram:
     2. 1 MB IO region
     3. Remaining region (4 GB - 1 MB - 4 KB) as 32-bit Non-Prefetchable MEM
 
+    .. note::
+
+      If the root complex is connected to an endpoint with virtual functions,
+      and the kernel panics during enumeration, add ``pci=realloc`` to ``optargs``
+      at the U-Boot prompt using the following command:
+
+      .. code-block:: console
+
+         setenv optargs 'pci=realloc'
+
+      The ``pci=realloc`` parameter instructs the Linux kernel to reallocate PCI
+      bridge resources. This helps resolve resource conflicts during enumeration
+      of PCIe devices by allowing the kernel to reassign memory and I/O addresses.
+
     .. rubric:: **Testing Details**
        :name: testing-details