Kernel: Fix type, dectivate_writes => deactivate_writes

Author: https://github.com/supercomputer7
Commit: 09d09b79b6
Pull-request: https://github.com/SerenityOS/serenity/pull/7258
Issue: https://github.com/SerenityOS/serenity/issues/7241
Reviewed-by: https://github.com/awesomekling
Reviewed-by: https://github.com/tomuta

Kernel/Graphics/FramebufferDevice.h

@@ -27,7 +27,7 @@ public:
     virtual mode_t required_mode() const override { return 0660; }
     virtual String device_name() const override;
 
-    virtual void dectivate_writes();
+    virtual void deactivate_writes();
     virtual void activate_writes();
     virtual size_t framebuffer_size_in_bytes() const { return m_framebuffer_pitch * m_framebuffer_height; }