target/ast10x0/backend/usart: remove orphan Cargo.toml

target/ast10x0/backend/usart/Cargo.toml

diff --git a/target/ast10x0/backend/usart/Cargo.toml b/target/ast10x0/backend/usart/Cargo.toml
deleted file mode 100644
index a221aa7..0000000
--- a/target/ast10x0/backend/usart/Cargo.toml
+++ /dev/null
@@ -1,7 +0,0 @@
-[package]
-name = "usart-backend-ast10x0"
-version = "0.1.0"
-edition = "2024"
-
-[dependencies]
-usart-api = { path = "../../../../drivers/usart/api" }