Camera: Update lensShadingMap documentation and visibility

Revert added language about shading map being the full flat-field
correction; it's actually the same correction as applied to
camera device-processed data.

Remove the Java lens shading map key from the NDK, since it's a
duplicate of the underlying native key already in NDK.

Also fix a few other wording issues in the lens shading documentation.

Bug: 18175853
Change-Id: I227707671914eb17b0a0dd14655ea732aae2a6b7
4 files changed