Netduino_USART: Add the Netduino Plus 2 USART Controller

This patch adds the Netduino Plus 2 USART controller
(UART also uses the same controller).

It can be used for reading and writing to the guest.

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PUBLIC
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Signed-off-by: Alistair Francis <alistair23@gmail.com>
Netduino_GPIO: Add the Netduino Plus 2 GPIO controller

This patch adds the Netduino Plus 2 GPIO controller to QEMU.
This allows reading and writing to the Netduino GPIO pins.

Signed-off-by: Alistair Francis <alistair23@gmail.com>
Netduino_SYSCFG: Add the Netduino Plus 2 SYSCFG

This patch adds the Netduino Plus 2 System Configuration
Controller. This is used to configure what memory is mapped
at address 0 (although that is not supported) as well
as configure how the EXTI interrupts work (also not
supported at the moment).

Signed-off-by: Alistair Francis <alistair23@gmail.com>
Netduino_Timer: Add the Netduino Plus 2 Timer2 to 5

This patch adds the Netduino Plus 2 timers: TIM2, TIM3, TIM4 and TIM5
to QEMU.

Signed-off-by: Alistair Francis <alistair23@gmail.com>
Netduino: Add the Netduino Plus 2 Machine Model

This patch adds the Netduion Plus 2 machine to QEMU.

Signed-off-by: Alistair Francis <alistair23@gmail.com>