iio: Documentation: Add additional *scale_available attributes
iio: Documentation: Add additional *scale_available attributes

Added some more *scale_available attributes to the list that
are used in various drivers but were missiong from Documentation.

Signed-off-by: Adriana Reus <54192c763ae4f960dbf2b2f913f2990b3167a436@intel.com>
Signed-off-by: Jonathan Cameron <09f65b71b7655725897b2fd41a09a0cefe2e1ace@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs