defconfig: lahaina-qgki: enable CONFIG_IIO

Enable CONFIG_IIO in lahaina_QGKI.config so that drivers which
depend upon it can function before CONFIG_IIO is enabled in
gki_defconfig.

Change-Id: I6afa93e6054d67157b1d435aa10688ab37220612
Signed-off-by: David Collins <collinsd@codeaurora.org>