ufs: ufs-qcom: Fix racing caused by ufs_qcom_testbus_config()

If func ufs_qcom_testbus_config() is invoked from ufshcd_suspend/resume
and/or clk gate/ungate context, pm_runtime_get_sync() and ufshcd_hold()
will flush the contexts calling ufs_qcom_testbus_config(), causing racing
problems. Fix it by removing the unnecessary calls of pm_runtime_get_sync()
and ufshcd_hold().

Change-Id: Iada1e777de0cafaf8c9b972fcace65399ea9668d
Signed-off-by: Can Guo <cang@codeaurora.org>