rhi: Skip comparing to this in isCompatible tests

Change-Id: Ie1855f992315f6e02986016a254127cec0ac94c8
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

src/gui/rhi/qrhi.cpp

@@ -2800,6 +2800,12 @@ QRhiResource::Type QRhiShaderResourceBindings::resourceType() const
  */
 bool QRhiShaderResourceBindings::isLayoutCompatible(const QRhiShaderResourceBindings *other) const
 {
+    if (other == this)
+        return true;
+
+    if (!other)
+        return false;
+
     const int count = m_bindings.count();
     if (count != other->m_bindings.count())
         return false;

src/gui/rhi/qrhivulkan.cpp

@@ -5845,6 +5845,9 @@ static inline bool attachmentDescriptionEquals(const VkAttachmentDescription &a,
 
 bool QVkRenderPassDescriptor::isCompatible(const QRhiRenderPassDescriptor *other) const
 {
+    if (other == this)
+        return true;
+
     if (!other)
         return false;