regmap: Implementation for regmap_multi_reg_write

This is the implementation of regmap_multi_reg_write()

There is a new capability 'can_multi_write' that device drivers
must set in order to use this multi reg write mode.

This replaces the first definition, which just defined the API.

Signed-off-by: Anthony Olech <anthony.olech.opensource@diasemi.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

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

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

diff --cc include/linux/regmap.h
Simple merge