Fix PlayStation build following 278797@main

https://bugs.webkit.org/show_bug.cgi?id=274205

Unreviewed build fix.

C++20 makes std::memory_order an enum class, which is pretty,
but the enum itself already existed, so we can use its values directly for greater compatibility.

* Source/WebCore/html/CanvasBase.cpp:
(WebCore::CanvasBase::memoryCost const):
(WebCore::CanvasBase::setImageBuffer const):
std::memory_order::relaxed -> std::memory_order_relaxed

Canonical link: https://commits.webkit.org/278806@main

Source/WebCore/html/CanvasBase.cpp

@@ -109,7 +109,7 @@ void CanvasBase::makeRenderingResultsAvailable(ShouldApplyPostProcessingToDirtyR
 size_t CanvasBase::memoryCost() const
 {
     // May be called from GC threads.
-    return m_imageBufferMemoryCost.load(std::memory_order::relaxed);
+    return m_imageBufferMemoryCost.load(std::memory_order_relaxed);
 }
 
 #if ENABLE(RESOURCE_USAGE)
@@ -259,7 +259,7 @@ RefPtr<ImageBuffer> CanvasBase::setImageBuffer(RefPtr<ImageBuffer>&& buffer) con
     RefPtr returnBuffer = std::exchange(m_imageBuffer, WTFMove(buffer));
 
     IntSize oldSize = m_size;
-    size_t oldMemoryCost = m_imageBufferMemoryCost.load(std::memory_order::relaxed);
+    size_t oldMemoryCost = m_imageBufferMemoryCost.load(std::memory_order_relaxed);
     size_t newMemoryCost = 0;
     if (m_imageBuffer) {
         m_size = m_imageBuffer->truncatedLogicalSize();
@@ -269,7 +269,7 @@ RefPtr<ImageBuffer> CanvasBase::setImageBuffer(RefPtr<ImageBuffer>&& buffer) con
         m_imageBuffer->context().setStrokeThickness(1);
         m_contextStateSaver = makeUnique<GraphicsContextStateSaver>(m_imageBuffer->context());
     }
-    m_imageBufferMemoryCost.store(newMemoryCost, std::memory_order::relaxed);
+    m_imageBufferMemoryCost.store(newMemoryCost, std::memory_order_relaxed);
     if (newMemoryCost) {
         JSC::JSLockHolder lock(scriptExecutionContext()->vm());
         scriptExecutionContext()->vm().heap.reportExtraMemoryAllocated(static_cast<JSCell*>(nullptr), newMemoryCost);