clk: qcom: clock-generic: Fix handoff for mux_div clock

The current implementation would check for the parent rate and decide the
handoff state of the clock, which is not true for mux clocks. With this
logic the function returns 'enabled' even when the clock downstream of this
clock is disabled. The handoff code will unnecessarily enable the current
parent of this clock.
If this function always returns 'disabled' and a clock downstream is on,
the clock handoff  code will bump up the ref count for this clock and its
current parent as necessary. The clocks without an actual HW gate can
always return handoff disabled.

Change-Id: I1f06842e2761b336b49a9390a556064de44f2e36
Signed-off-by: Taniya Das <tdas@codeaurora.org>