remove (unnecessary) SkScalarMul and SkScalarMulAdd macros from SkMatrix.cpp.

SkScalarMulDiv remains, but it can be removed later (though it is slightly clearer to use it at times).

BUG=skia:
R=caryclark@google.com, mtklein@google.com, halcanary@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/150493002

git-svn-id: http://skia.googlecode.com/svn/trunk@13252 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed