Kernel: Fix always-true comparison warnings

Author: https://github.com/BertalanD
Commit: https://github.com/SerenityOS/serenity/commit/fda9f394d14
Pull-request: https://github.com/SerenityOS/serenity/pull/8354
Reviewed-by: https://github.com/Hendiadyoin1
Reviewed-by: https://github.com/alimpfard

Kernel/KBuffer.h

@@ -64,7 +64,7 @@ public:
         auto new_region = MM.allocate_kernel_region(page_round_up(new_capacity), m_region->name(), m_region->access(), m_allocation_strategy);
         if (!new_region)
             return false;
-        if (m_region && m_size > 0)
+        if (m_size > 0)
             memcpy(new_region->vaddr().as_ptr(), data(), min(m_region->size(), m_size));
         m_region = new_region.release_nonnull();
         return true;

Kernel/Scheduler.cpp

@@ -460,7 +460,7 @@ Process* Scheduler::colonel()
 
 UNMAP_AFTER_INIT void Scheduler::initialize()
 {
-    VERIFY(&Processor::current() != nullptr); // sanity check
+    VERIFY(Processor::is_initialized()); // sanity check
 
     RefPtr<Thread> idle_thread;
     g_finalizer_wait_queue = new WaitQueue;