`limit()` is the same for all lanes, so use `rr::Int`, not `SIMD::Int`.
This was using an unqualified scope, so likely just a screwup when I first wrote this.

Bug: None. A simple fix.
Change-Id: I0df67fb88f9973dd522a5555888173ba1f5ae594
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/48689Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Ben Clayton <bclayton@google.com>