Fix two incorrect Rustdoc source-tree paths

[younes-io]

I found two incorrect source-tree paths in the current rust-next documentation:

• rust/kernel/print.rs links _printk to include/linux/_printk.h, which does not exist. _printk is declared in include/linux/printk.h

linux/rust/kernel/print.rs

Lines 93 to 102 in 7059bdf

	/// Prints a message via the kernel's [`_printk`].
	///
	/// Public but hidden since it should only be used from public macros.
	///
	/// # Safety
	///
	/// The format string must be one of the ones in [`format_strings`], and
	/// the module name must be null-terminated.
	///
	/// [`_printk`]: srctree/include/linux/_printk.h

• rust/kernel/irq.rs displays include/linux/device.h, while the link points to include/linux/interrupt.h. The displayed path should also be include/linux/interrupt.h

linux/rust/kernel/irq.rs

Lines 3 to 11 in 7059bdf

	//! IRQ abstractions.
	//!
	//! An IRQ is an interrupt request from a device. It is used to get the CPU's
	//! attention so it can service a hardware event in a timely manner.
	//!
	//! The current abstractions handle IRQ requests and handlers, i.e.: it allows
	//! drivers to register a handler for a given IRQ line.
	//!
	//! C header: [`include/linux/device.h`](srctree/include/linux/interrupt.h)

@ojeda @dakr, would it be okay to fix both in one small patch, or should the IRQ change be separate?

[ojeda]

Separate is usually best -- they will need different Fixes: tags anyway.