ARM: dts: qcom: Remove L3 power levels from GPU dtsi

As of now we are not using l3_vote clock in lito, and
without this clock, l3 power levels are not useful.
So removing l3-pwrlevels from gpu dtsi to prevent l3_vote
clock related errors from driver.

Change-Id: I8c7464d84b59177f46785647804ebb9e6db42a30