scsi: ufs-qcom: Implement device_reset vops

The UFS_RESET pin on Qualcomm SoCs are controlled by TLMM and exposed
through the GPIO framework. Acquire the device-reset GPIO and use this
to implement the device_reset vops, to allow resetting the attached
memory.

Based on downstream support implemented by Subhash Jadavani
<subhashj@codeaurora.org>.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>