soc: qcom: socinfo: Expose custom attributes

The Qualcomm socinfo provides a number of additional attributes,
add these to the socinfo driver and expose them via debugfs
functionality.

Tested-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Vaishali Thakkar <vaishali.thakkar@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>