ARM: dts: msm: add blink support for GPLED

Existing implementation does not support blink functionality for
GPLED. Add a DT parameter qcom,use-blink to add blink sysfs entry
for switching into lpg mode when GPLED is to be used for blinking.

Change-Id: I1d502eba30d87f3f7e6439d6a4d4e4d286d84528
Signed-off-by: Abinaya P <abinayap@codeaurora.org>