Update dependencies `riscv` and `spin`

Cargo.toml

@@ -27,6 +27,6 @@ targets = [
 [dependencies]
 embedded-hal = "0.2.6"
 nb = "1.0"
-riscv = "0.6"
-spin = "0.7"
+riscv = "0.7"
+spin = "0.9"
 lazy_static = { version = "1", features = ["spin_no_std"] }