ANDROID: GKI: rockchip: Enable symbols for iio

Functions changes summary: 0 Removed, 0 Changed (424 filtered out), 2 Added functions
Variables changes summary: 0 Removed, 0 Changed (3 filtered out), 0 Added variables

2 Added functions:

  [A] 'function void iio_channel_release_all(iio_channel*)'
  [A] 'function int iio_update_buffers(iio_dev*, iio_buffer*, iio_buffer*)'

Bug: 194515348
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ifaaade732fa2372e9d8c31483f52188c227eac13