Kernel: Simplify some if statements

Kernel/GlobalProcessExposed.cpp

@@ -336,9 +336,7 @@ private:
     ProcFSSelfProcessDirectory();
     virtual bool acquire_link(KBufferBuilder& builder) override
     {
-        if (builder.appendff("{}", Process::current().pid().value()).is_error())
-            return false;
-        return true;
+        return !builder.appendff("{}", Process::current().pid().value()).is_error();
     }
 };
 

Kernel/Scheduler.cpp

@@ -517,7 +517,7 @@ void Scheduler::invoke_async()
 
 void Scheduler::notify_finalizer()
 {
-    if (g_finalizer_has_work.exchange(true, AK::MemoryOrder::memory_order_acq_rel) == false)
+    if (!g_finalizer_has_work.exchange(true, AK::MemoryOrder::memory_order_acq_rel))
         g_finalizer_wait_queue->wake_all();
 }
 

Kernel/kprintf.cpp

@@ -61,10 +61,7 @@ static void serial_putch(char ch)
 
     IO::out8(0x3F8, ch);
 
-    if (ch == '\r')
-        was_cr = true;
-    else
-        was_cr = false;
+    was_cr = ch == '\r';
 }
 
 static void critical_console_out(char ch)