Clarify negativeOneToOne depth clipping comments
Clarify negativeOneToOne depth clipping comments

While VK_EXT_depth_clip_control affects both the viewport transform and
primitive clipping, the latter is not concerned with how the z
coordinate gets mapped between the near and far frustum plane. Therefore
to avoid confusion the comment which mentioned such mapping has been
removed. For the clipping code we only need to know that the position of
the near clipping plane changes.

Bug: b/207658159
Change-Id: I40fd1c82c85a1841de91d22f137d8fa925ec0ada
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/67688
Reviewed-by: Shahbaz Youssefi <582eeec4f08a2ccd61e3ef52115e6e7c571582de@google.com>
Tested-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Kokoro-Result: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

google/swiftshader,google/swiftshader,google/swiftshader