arm64: dts: qcom: sm8250: Fix device name for ufs controller

Change ufs controller dev name from ufs@1d84000 to ufshc@1d84000. Without
this change when ufs controller is built in as part of kernel, the driver
code fails to initialize the device  due to a check against
android.bootdevice.(The validity and reason for this check in the driver
code needs to be revisited. But the change in device name allows ufs
controller to be registered during boot). This change also makes the dev
name compatible with how it is defined for other Qualcomm SoCs.

Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>