[kernel] Get rid of obsolete thread loading state

The thread::state::loading flag was left over from a time when the
kernel did elf loading for all processes.

src/kernel/objects/thread.cpp

@@ -20,7 +20,7 @@ static constexpr j6_signal_t thread_default_signals = 0;
 thread::thread(process &parent, uint8_t pri, uintptr_t rsp0) :
     kobject(kobject::type::thread, thread_default_signals),
     m_parent(parent),
-    m_state(state::loading),
+    m_state(state::none),
     m_wait_type(wait_type::none),
     m_wait_data(0),
     m_wait_obj(0)

src/kernel/objects/thread.h

@@ -67,11 +67,11 @@ public:
     constexpr static j6_cap_t parent_caps = j6_cap_thread_all;
 
     enum class state : uint8_t {
+        none     = 0x00,
         ready    = 0x01,
-        loading  = 0x02,
-        exited   = 0x04,
-        constant = 0x80,
-        none     = 0x00
+        exited   = 0x02,
+
+        constant = 0x80
     };
 
     /// Destructor
@@ -86,10 +86,6 @@ public:
     /// \returns True if the thread is ready to execute.
     inline bool ready() const { return has_state(state::ready); }
 
-    /// Get the `loading` state of the thread.
-    /// \returns True if the thread has not finished loading.
-    inline bool loading() const { return has_state(state::loading); }
-
     /// Get the `constant` state of the thread.
     /// \returns True if the thread has constant priority.
     inline bool constant() const { return has_state(state::constant); }