rust: include rust_version in Cargo.toml

Tell clippy the minimum supported Rust version for QEMU.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/rust/hw/char/pl011/Cargo.toml b/rust/hw/char/pl011/Cargo.toml
index 2b40978..f2296ca 100644
--- a/rust/hw/char/pl011/Cargo.toml
+++ b/rust/hw/char/pl011/Cargo.toml
@@ -9,6 +9,7 @@
 publish = false
 keywords = []
 categories = []
+rust-version = "1.63.0"
 
 [lib]
 crate-type = ["staticlib"]
diff --git a/rust/hw/char/pl011/src/device_class.rs b/rust/hw/char/pl011/src/device_class.rs
index 8a157a6..dbef93f 100644
--- a/rust/hw/char/pl011/src/device_class.rs
+++ b/rust/hw/char/pl011/src/device_class.rs
@@ -12,7 +12,6 @@
 
 use crate::device::{PL011Registers, PL011State};
 
-#[allow(clippy::missing_const_for_fn)]
 extern "C" fn pl011_clock_needed(opaque: *mut c_void) -> bool {
     let state = NonNull::new(opaque).unwrap().cast::<PL011State>();
     unsafe { state.as_ref().migrate_clock }
diff --git a/rust/qemu-api-macros/Cargo.toml b/rust/qemu-api-macros/Cargo.toml
index b9b4bae..89dee1c 100644
--- a/rust/qemu-api-macros/Cargo.toml
+++ b/rust/qemu-api-macros/Cargo.toml
@@ -9,6 +9,7 @@
 publish = false
 keywords = []
 categories = []
+rust-version = "1.63.0"
 
 [lib]
 proc-macro = true
diff --git a/rust/qemu-api/Cargo.toml b/rust/qemu-api/Cargo.toml
index 4aa22f3..a51dd14 100644
--- a/rust/qemu-api/Cargo.toml
+++ b/rust/qemu-api/Cargo.toml
@@ -12,6 +12,7 @@
 publish = false
 keywords = []
 categories = []
+rust-version = "1.63.0"
 
 [dependencies]
 qemu_api_macros = { path = "../qemu-api-macros" }