remove confusing wording in rationale

Author: gnzlbg

text/0000-simd-ffi.md

@@ -182,9 +182,7 @@ TBD.
 # Rationale and alternatives
 [rationale-and-alternatives]: #rationale-and-alternatives
 
-This is an adhoc solution to the problem. This RFC does not explore more general
-mechanisms of dealing with, or abstracting over, `target_feature`s associated
-with the SIMD vector types for FFI purposes.
+This is an adhoc solution to the problem, but sufficient for FFI purposes.
 
 ## Future architecture-specific vector types