Contracts build risc-v fixtures (#2554)

Follow up from #2347 this time to verify that fixtures build to RISC-V

---------

Co-authored-by: alvicsam <alvicsam@gmail.com>
Co-authored-by: Alexander Samusev <41779041+alvicsam@users.noreply.github.com>
Co-authored-by: Alexander Theißen <alex.theissen@me.com>

substrate/frame/contracts/uapi/Cargo.toml

@@ -8,8 +8,9 @@ homepage = "https://substrate.io"
 repository.workspace = true
 description = "Exposes all the host functions that a contract can import."
 
-[lints]
-workspace = true
+# [lints]
+# TODO: uncomment when rve toolchain is updated to rust 1.74 or greater.
+# workspace = true
 
 [dependencies]
 paste = { version = "1.0", default-features = false }
@@ -20,6 +21,9 @@ scale = { package = "parity-scale-codec", version = "3.6.1", default-features =
 	"max-encoded-len",
 ], optional = true }
 
+[target.'cfg(target_arch = "riscv32")'.dependencies]
+polkavm-derive = '0.2.0'
+
 [features]
 default = ["scale"]
 scale = ["dep:scale", "scale-info"]