scsi: ufs: Give clk scaling min gear a value

The initialization of clk_scaling.min_gear was removed by mistake. This
change adds it back, otherwise clock scaling down would fail.

Link: https://lore.kernel.org/r/1611802172-37802-1-git-send-email-cang@codeaurora.org
Fixes: 4543d9d7

 ("scsi: ufs: Refactor ufshcd_init/exit_clk_scaling/gating()")
Reported-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Tested-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>