Update crate profile and license

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
+# RustSBI library and all supported platforms
 members = [
     "rustsbi",
-    "platform/k210",
-    "platform/qemu",
+    "platform/*",
 ]

rustsbi/Cargo.toml

@@ -4,8 +4,9 @@ description = "Minimal RISC-V's SBI implementation library in Rust"
 version = "0.0.2"
 authors = ["luojia65 <[email protected]>"]
 repository = "https://github.com/luojia65/rustsbi"
-license = "MIT" # OR MulanPSL-2.0; cargo does not support by now
-license-file = "../LICENSE-MULAN"
+documentation = "https://docs.rs/rustsbi"
+license = "MIT OR MulanPSL-2.0"
+readme = "../README.md"
 keywords = ["riscv", "sbi", "rustsbi"]
 categories = ["os", "embedded", "hardware-support", "no-std"]
 edition = "2018"