hw/arm/musicpal: Remove nonexistent CDTP2, CDTP3 registers

The ethernet device in the musicpal only has two tx queues,
but we modelled it with four CTDP registers, presumably a
cut and paste from the rx queue registers. Since the tx_queue[]
array is only 2 entries long this allowed a guest to overrun
this buffer. Remove the nonexistent registers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1392737293-10073-1-git-send-email-peter.maydell@linaro.org
Acked-by: Jan Kiszka <jan.kiszka@web.de>
Cc: qemu-stable@nongnu.org
