ASoC: bcm2835: move to use the clock framework

Since the move to the new clock framework with commit 94cb7f76
("ARM: bcm2835: Switch to using the new clock driver support.")
this driver was no longer functional as it was manipulating the
clock registers locally without going true the framework.

This patch moves to use the new clock framework and also
moves away from the hardcoded address offsets for DMA getting
the dma-address directly from the device tree.

Note that the optimal bclk_ratio selection to avoid jitter
due to the use of fractional dividers, which is in the
current version has been removed, because not all devices
support these non power of 2 sized transfers, which resulted
in lots of (downstream) modules that use:
  snd_soc_dai_set_bclk_ratio(cpu_dai, sample_bits * 2);
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>