ARM: dts: msm: Remove RRADC channel nodes on pmicobalt

ARM: dts: msm: Remove RRADC channel nodes on pmicobalt

Currently there are no channel specific properties associated
with the RRADC channels. The existing channel nodes specify
a logical channel number that is used by the client when
requesting the RRADC channel read. This can instead be obtained
from the channel list specified within the driver. Therefore
remove the channel nodes.

Change-Id: I4da81a576b88285cedb0a1c7fd49ccd526d25012
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>