buffer_cache: Minor fixes

Loop through the tmp_intervals by reference, rather than by copy, and fix gl clear buffer size calculation.

src/video_core/renderer_opengl/gl_buffer_cache.cpp

@@ -147,8 +147,7 @@ void BufferCacheRuntime::CopyBuffer(Buffer& dst_buffer, Buffer& src_buffer,
 
 void BufferCacheRuntime::ClearBuffer(Buffer& dest_buffer, u32 offset, size_t size, u32 value) {
     glClearNamedBufferSubData(dest_buffer.Handle(), GL_R32UI, static_cast<GLintptr>(offset),
-                              static_cast<GLsizeiptr>(size / sizeof(u32)), GL_RED, GL_UNSIGNED_INT,
-                              &value);
+                              static_cast<GLsizeiptr>(size), GL_RED, GL_UNSIGNED_INT, &value);
 }
 
 void BufferCacheRuntime::BindIndexBuffer(Buffer& buffer, u32 offset, u32 size) {