regmap: add support to regmap_field_bulk_alloc/free apis

regmap: add support to regmap_field_bulk_alloc/free apis

Usage of regmap_field_alloc becomes much overhead when number of fields
exceed more than 3.
QCOM LPASS driver has extensively converted to use regmap_fields.

Using new bulk api to allocate fields makes it much more cleaner code to read!

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Srinivasa Rao Mandadapu <srivasam@codeaurora.org>
Link: https://lore.kernel.org/r/20200925164856.10315-2-srinivas.kandagatla@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>