Kernel/LibC: Rework TIOC{G,S}WINSZ more linux like

Userspace can freely set terminal size, kernel just updates it when for
example new font is loaded. Also SIGWINCH is now sent by kernel instead
of userspace.

kernel/kernel/Terminal/Serial.cpp

@@ -181,7 +181,9 @@ namespace Kernel
 		  }, 0600, 0, 0)
 		, m_name(MUST(BAN::String::formatted("ttyS{}", s_next_tty_number++)))
 		, m_serial(serial)
-	{}
+	{
+		update_winsize(m_serial.width(), m_serial.height());
+	}
 
 	BAN::ErrorOr<BAN::RefPtr<SerialTTY>> SerialTTY::create(Serial serial)
 	{
@@ -254,16 +256,6 @@ namespace Kernel
 			handle_input_byte(*ptr++);
 	}
 
-	uint32_t SerialTTY::width() const
-	{
-		return m_serial.width();
-	}
-
-	uint32_t SerialTTY::height() const
-	{
-		return m_serial.height();
-	}
-
 	bool SerialTTY::putchar_impl(uint8_t ch)
 	{
 		m_serial.putchar(ch);