opencv3: fix CUDA code generation
opencv3: fix CUDA code generation

Formula was hardcoded to generate code specifically for the Kepler architecture, causing the CUDA modules not to work on any other architecture.

Closes #5903.

Signed-off-by: Michka Popoff <7b0496f66f66ee22a38826c310c38b415671b832@gmail.com>

andrewjpage/homebrew-science,dpo/homebrew-science,pditommaso/homebrew-science,quantumsteve/homebrew-science,heuermh/homebrew-science