clk: qcom: clk-smd-rpm: Fix the reported rate of branches

As there is no way to actually query the hardware for the current clock
rate, now racalc_rate() just returns the last rate that was previously
set. But if the rate was not set yet, we return the bogus rate of 1000Hz.

The branch clocks have the same rate as their parent, so in this case we
just need to remove recalc_rate ops and then the core framework will handle
this automagically. The round_rate() is unused, so remove it as well.

Reported-by: Archit Taneja <architt@codeaurora.org>
Fixes: 00f64b58 ("clk: qcom: Add support for SMD-RPM Clocks")
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>