scsi: ufs-qcom: Add sysfs for a debug state

This sysfs entry provides the state of the driver.
If it's in debug/perf state.
This can be used by user-space scripts to toggle various tracing.

Change-Id: If0e3d8e032f60c9134bdd5ce27fe37687e67770a
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>