Fix build: these asserts are always now true, which GCC warns about

src/pipe/SkGPipeRead.cpp

Index: src/pipe/SkGPipeRead.cpp
diff --git a/src/pipe/SkGPipeRead.cpp b/src/pipe/SkGPipeRead.cpp
index af3ec1ee04cd2d2e1977c95c4ca5d26fe20e9a1c..41c417f92ecda9fbec95e6070975ecd58ef502c9 100644
--- a/src/pipe/SkGPipeRead.cpp
+++ b/src/pipe/SkGPipeRead.cpp
@@ -231,14 +231,12 @@ private:
 ///////////////////////////////////////////////////////////////////////////////
 
 template <typename T> const T* skip(SkReader32* reader, size_t count = 1) {
-    SkASSERT(count >= 0);
     size_t size = sizeof(T) * count;
     SkASSERT(SkAlign4(size) == size);
     return reinterpret_cast<const T*>(reader->skip(size));
 }
 
 template <typename T> const T* skipAlign(SkReader32* reader, size_t count = 1) {
-    SkASSERT(count >= 0);
     size_t size = SkAlign4(sizeof(T) * count);
     return reinterpret_cast<const T*>(reader->skip(size));
 }