clk: qcom: Fix duplicate rbcpr clock name

There is a duplication in a clock name for apq8084 platform that causes
the following warning: "RBCPR_CLK_SRC" redefined

Resolve this by adding a MMSS_ prefix to this clock and making its name
coherent with msm8974 platform.

Fixes: 2b46cd23

 ("clk: qcom: Add APQ8084 Multimedia Clock Controller (MMCC) support")
Signed-off-by: Georgi Djakov <gdjakov@mm-sol.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>