gl_stream_buffer/vk_staging_buffer_pool: Fix size check

Fix a tragic off-by-one condition that causes Vulkan's stream buffer to
think it's always full, using fallback memory. The OpenGL was also
affected by this bug to a lesser extent.

src/video_core/renderer_opengl/gl_stream_buffer.cpp

@@ -40,7 +40,7 @@ std::pair<std::span<u8>, size_t> StreamBuffer::Request(size_t size) noexcept {
         glClientWaitSync(fences[region].handle, 0, GL_TIMEOUT_IGNORED);
         fences[region].Release();
     }
-    if (iterator + size > free_iterator) {
+    if (iterator + size >= free_iterator) {
         free_iterator = iterator + size;
     }
     if (iterator + size > STREAM_BUFFER_SIZE) {

src/video_core/renderer_vulkan/vk_staging_buffer_pool.cpp

@@ -153,7 +153,7 @@ StagingBufferRef StagingBufferPool::GetStreamBuffer(size_t size) {
     used_iterator = iterator;
     free_iterator = std::max(free_iterator, iterator + size);
 
-    if (iterator + size > STREAM_BUFFER_SIZE) {
+    if (iterator + size >= STREAM_BUFFER_SIZE) {
         std::fill(sync_ticks.begin() + Region(used_iterator), sync_ticks.begin() + NUM_SYNCS,
                   current_tick);
         used_iterator = 0;