rust: pci: implement TryInto<IrqRequest<'a>> for IrqVector<'a>

rust: pci: implement TryInto<IrqRequest<'a>> for IrqVector<'a>

Implement TryInto<IrqRequest<'a>> for IrqVector<'a> to directly convert
a pci::IrqVector into a generic IrqRequest, instead of taking the
indirection via an unrelated pci::Device method.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>