This CL fixes a minor compiler warning related to the use of 0xFFFFFFFF
to divide a float value. It turns out that this integer value cannot be
converted to a float without losing one bit of accuracy.

Bug: None
Change-Id: I34fefd91afb526edbfafd3d8a2378fa6b7bf325d
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/38448Reviewed-by: Ben Clayton <bclayton@google.com>
Tested-by: David Turner <digit@google.com>
Kokoro-Presubmit: David Turner <digit@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>