Revert "scsi: ufs: add some custom testbus register reads for debugging purpose"

This reverts commit 6bdc0ae2.

As it adds unnecessary overhead and was only intended for debug purpose.

Change-Id: Ie8500c012f3df05de018c9fd9601fe54a01a0315
Signed-off-by: Can Guo <cang@codeaurora.org>