Second round of IIO fixes for the 3.13 cycle. 2 fixes here. * The gp2ap020a00f is a simple missing kconfig dependency. * The hid sensors hub fix is a work around for an issue introduced by hardware changes due to a certain large software vendor having an 'interesting' interpretation of the specification and hence indexing some arrays from 1 rather than 0. The fix takes advantage of the logical min and max reading facilities introduced by the precursor patch to figure out whether we have a 0 indexed or 1 indexed device and to adjust appropriately. It also drops a previous kconfig option that allowed this issue to be worked around at build time.