arm64: dts: hikey: extend default cma size to 128MB

To support display in Debian on HiKey, cma heap is used to allocate
graphic buffers. The default size of CMA is 16 MB which is not enough.

Increase the default CMA size to 128 MB.

cc: Fathi Boudra <fathi.boudra@linaro.org>
cc: John Stultz <john.stultz@linaro.org>
cc: Xinliang Liu <xinliang.liu@linaro.org>
Signed-off-by: Guodong Xu <guodong.xu@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>