ARM: dts: qcom: msm8960: add gsbi8 and its serial configuration

ARM: dts: qcom: msm8960: add gsbi8 and its serial configuration

The LTE variant of the MSM8960 SoC has a gsbi8 node used for the
serial console.

That's if the downstream kernel is to be believed, as Xperia SP has
a serial console on gsbi8 even on the non-LTE variant.

Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250623-msm8960-sdcard-v2-2-340a5e8f7df0@smankusors.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>