In case the "core_clk_unipro" clock is not provided, "cycles_in_1us"
variable will be used as uninitialized. So initialize it with 0.

Issue reported by Smatch tool:

drivers/ufs/host/ufs-qcom.c:1336 ufs_qcom_set_core_clk_ctrl() error: uninitialized symbol 'cycles_in_1us'.
drivers/ufs/host/ufs-qcom.c:1341 ufs_qcom_set_core_clk_ctrl() error: uninitialized symbol 'cycles_in_1us'.
Reviewed-by: Nitin Rawat <quic_nitirawa@quicinc.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20231208065902.11006-14-manivannan.sadhasivam@linaro.org
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sa8775p-ride
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>