ARM: dts: msm: Use PM8916 LBC primary charger for apq8009 Dragon Board

PM8916 is the primary charger on the apq8009 dragon board,

remove the 'external-charger' config from it.

Change-Id: Ia6620a0aa7c98751fce1a8f8d45b4b95e24aadca
Signed-off-by: Madhukar Sandi <msandi@codeaurora.org>