regmap: Move the handling for max_raw_read into regmap_raw_read

Currently regmap_bulk_read will split a read into chunks before
calling regmap_raw_read if max_raw_read is set. It is more logical for
this handling to be inside regmap_raw_read itself, as this removes the
need to keep re-implementing the chunking code, which would be the
same for all users of regmap_raw_read.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>