soc: qcom: llc-slice: Add missing MODULE_LICENSE()

Add missing MODULE_LICENSE().
According to the SPDX-License-Identifier, the license is GPL v2.

Fixes the following warning:
WARNING: modpost: missing MODULE_LICENSE() in drivers/soc/qcom/llcc-slice.o

Fixes: a3134fb0 ("drivers: soc: Add LLCC driver")
Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>