Revert of Fix compilation error when building with clang on Linux.

Revert of Fix compilation error when building with clang on Linux. (https://codereview.chromium.org/287193006/)

Reason for revert:
need to revert this along with reverting the big unitmapper cl

Original issue's description:
> Fix compilation error when building with clang on Linux.
> 
> ../../src/effects/gradients/SkGradientShader.cpp:487:22: error: unused
> function 'bitsTo16' [-Werror,-Wunused-function]
> static inline U16CPU bitsTo16(unsigned x, const unsigned bits) {
> 
> R=bsalomon@google.com
> TEST=make tests
> 
> Committed: http://code.google.com/p/skia/source/detail?r=14835

TBR=bsalomon@google.com,reed@google.com,tfarina@chromium.org
NOTREECHECKS=true
NOTRY=true

Committed: http://code.google.com/p/skia/source/detail?r=14839

[reed2, 2014-05-22 03:19:35]

Created Revert of Fix compilation error when building with clang on Linux.

[commit-bot: I haz the power, 2014-05-22 03:20:24]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/reed@chromium.org/297803010/1

[commit-bot: I haz the power, 2014-05-22 03:20:51]

Change committed as 14839