mesa: Move the mvp_with_dp4 flag to ShaderCompilerOptions.

mesa: Move the mvp_with_dp4 flag to ShaderCompilerOptions.

This flag essentially tells the compiler whether it prefers
dot products or multiply/adds for matrix operations.  As such,
ShaderCompilerOptions seems like the right place for it.

This also lets us specify it on a per-stage basis.  This patch makes all
existing users set the flag for the Vertex Shader stage only, as it's
currently only used for fixed-function vertex programs.  That will
change soon, and I wanted to preserve the existing behavior.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>