ARM: dts: msm: select external rsense for msm8226-skuf-v2 QRD

Since external rsense is used instead of internal one,
use-external-rsense should be enabled in the device tree.

Change-Id: Ifd573c46c7892bc52e6a88dc1b5c47e98de24b03
Signed-off-by: Xu Kai <kaixu@codeaurora.org>