tweak docs wording

Author: japaric

src/lib.rs

@@ -106,9 +106,8 @@
 //! When this feature is disabled semihosting is implemented using FFI calls into an external
 //! assembly file and compiling this crate works on stable and beta.
 //!
-//! Apart from the toolchain requirement, disabling `inline-asm` requires `arm-none-eabi-gcc` to be
-//! installed on the host. Also, disabling `inline-asm` imposes an overhead of an extra function
-//! call on each semihosting call compared to having `inline-asm` enabled.
+//! Apart from the toolchain requirement, enabling `inline-asm` removes the requirement of having
+//! `arm-none-eabi-gcc` installed on the host.
 //!
 //! # Reference
 //!