Revert "regmap: Add bulk read/write callbacks into regmap_config"

This reverts commit b96b0179 which is
commit d77e7456 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Icf14fb2d16a8460df4ef8a74e221d4526faa1f90
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>