regmap: core: Make raw write available to regcache

This allows the cache to sync values directly to the device when stored
in native format and also allows asynchronous I/O.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

diff --cc drivers/base/regmap/internal.h
Simple merge

diff --cc drivers/base/regmap/regmap.c
Simple merge