bcm2836pwm doesn't work on BCM2711

[mariobalanica]

This is being used by rpiwav to generate analog audio.

The first change is that now there are two PWM peripherals (and PWM0, which is the only PWM peripheral currently described in ACPI, can't be muxed to the audio jack pins anymore).

From what I've seen, the addresses for PWM0 haven't changed, but the driver now fails to do DMA (even with the range being limited at the first 1 GB).