ARM: dts: msm: Set system load for LDO13

Add system_load property for LDO13 since TP need this LDO keep NPM
when we wake up system by click TP. Or else, system will crash because
of lacking of driver strength.

Change-Id: I56e0cda4c87339296dd76af4e23b3a7fb171ab1f
Signed-off-by: keqili <keqili@codeaurora.org>