bcm2835-dma: Add proper 40-bit DMA support

raspberrypi inclusion
category: feature
bugzilla: 50432

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BCM2711 has 4 DMA channels with a 40-bit address range, allowing them
to access the full 4GB of memory on a Pi 4.
Signed-off-by: NPhil Elwell <phil@raspberrypi.org>
Signed-off-by: NFang Yafen <yafen@iscas.ac.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>