Make GrRenderableConfigForColorSpace argument const

src/gpu/SkGr.cpp

Index: src/gpu/SkGr.cpp
diff --git a/src/gpu/SkGr.cpp b/src/gpu/SkGr.cpp
index 9ee8722afa0eb213dd9d40709e7b761b74c1f6f0..6d1e73552d9653e54d80ccb29bdec40fb3c8ed10 100644
--- a/src/gpu/SkGr.cpp
+++ b/src/gpu/SkGr.cpp
@@ -508,7 +508,7 @@ bool GrPixelConfigToColorType(GrPixelConfig config, SkColorType* ctOut) {
     return true;
 }
 
-GrPixelConfig GrRenderableConfigForColorSpace(SkColorSpace* colorSpace) {
+GrPixelConfig GrRenderableConfigForColorSpace(const SkColorSpace* colorSpace) {
     if (!colorSpace) {
         return kRGBA_8888_GrPixelConfig;
     } else if (colorSpace->gammaIsLinear()) {