Keeping Makefile and Kconfig entries in alphabetical order usually works better
than just appending new entries at the end, since it reduces the amount of
conflicts. This patch adds a comment to the IIO Kconfig and Makefile files to
document that the entries should be kept in alphabetical order.

Also reorder those  entries which weren't in alphabetical order yet.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Changes since V1:

Apply review feedback:
	Introduce and use IIO_CHAN_INFO_HARDWAREGAIN
	Introduce and use Use IIO_VAL_INT_PLUS_MICRO_DB

Modify out of staging include paths.
Convert to new iio core API naming.

Changes since V2:

more sanity checking in write_raw
Signed-off-by: NMichael Hennerich <michael.hennerich@analog.com>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>