Kernel: Make TimeManagement::boot_time() static

Kernel/Time/TimeManagement.cpp

@@ -175,7 +175,7 @@ time_t TimeManagement::ticks_per_second() const
     return m_time_keeper_timer->ticks_per_second();
 }
 
-time_t TimeManagement::boot_time() const
+time_t TimeManagement::boot_time()
 {
     return RTC::boot_time();
 }

Kernel/Time/TimeManagement.h

@@ -47,7 +47,7 @@ public:
     Time epoch_time(TimePrecision = TimePrecision::Precise) const;
     void set_epoch_time(Time);
     time_t ticks_per_second() const;
-    time_t boot_time() const;
+    static time_t boot_time();
 
     bool is_system_timer(HardwareTimerBase const&) const;