rust: pci: refer to legacy as INTx interrupts

Consistently use INTx, as in the description of IrqType::Intx, to refer
to the four legacy PCI interrupts, INTA#, INTB#, INTC#, and INTD#.

Link: https://lore.kernel.org/rust-for-linux/20251015230209.GA960343@bhelgaas/
Link: https://github.com/Rust-for-Linux/linux/issues/1196
Suggested-by: Bjorn Helgaas <[e-mail]>
Signed-off-by: Peter Colberg <[e-mail]>
Signed-off-by: Danilo Krummrich <[e-mail]>

rust/kernel/pci/irq.rs

···
 pub struct IrqTypes(u32);
 
 impl IrqTypes {
-    /// Create a set containing all IRQ types (MSI-X, MSI, and Legacy).
+    /// Create a set containing all IRQ types (MSI-X, MSI, and INTx).
     pub const fn all() -> Self {
         Self(bindings::PCI_IRQ_ALL_TYPES)
     }
···
     /// # Examples
     ///
     /// ```ignore
-    /// // Create a set with only MSI and MSI-X (no legacy interrupts).
+    /// // Create a set with only MSI and MSI-X (no INTx interrupts).
     /// let msi_only = IrqTypes::default()
     ///     .with(IrqType::Msi)
     ///     .with(IrqType::MsiX);
···
     /// Allocate IRQ vectors for this PCI device with automatic cleanup.
     ///
     /// Allocates between `min_vecs` and `max_vecs` interrupt vectors for the device.
-    /// The allocation will use MSI-X, MSI, or legacy interrupts based on the `irq_types`
+    /// The allocation will use MSI-X, MSI, or INTx interrupts based on the `irq_types`
     /// parameter and hardware capabilities. When multiple types are specified, the kernel
-    /// will try them in order of preference: MSI-X first, then MSI, then legacy interrupts.
+    /// will try them in order of preference: MSI-X first, then MSI, then INTx interrupts.
     ///
     /// The allocated vectors are automatically freed when the device is unbound, using the
     /// devres (device resource management) system.
···
     /// // Allocate using any available interrupt type in the order mentioned above.
     /// let vectors = dev.alloc_irq_vectors(1, 32, pci::IrqTypes::all())?;
     ///
-    /// // Allocate MSI or MSI-X only (no legacy interrupts).
+    /// // Allocate MSI or MSI-X only (no INTx interrupts).
     /// let msi_only = pci::IrqTypes::default()
     ///     .with(pci::IrqType::Msi)
     ///     .with(pci::IrqType::MsiX);