The regmap binding talks about one thing, which is register
endianess, and it gets almost every aspect of it wrong.

This replaces the current text of the file with a version
that makes more sense and that matches what we implement
now.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: a06c488d ("regmap: Add explict native endian flag to DT bindings")
Fixes: 275876e2 ("regmap: Add the DT binding documentation for endianness")
Signed-off-by: Mark Brown <broonie@kernel.org>