arm64: dts: msm8998-mtp: Add pm8005_s1 regulator

The pm8005_s1 is VDD_GFX, and needs to be on to enable the GPU.
This should be hooked up to the GPU CPR, but we don't have support for that
yet, so until then, just turn on the regulator and keep it on so that we
can focus on basic GPU bringup.

Signed-off-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>