clk: qcom: add gcc-msm8939: Add missing system_mm_noc_bfdcd_clk_src

The msm8939 has an additional higher operating point for the multi-media
peripherals. The higher throughput MM componets operate off of the
system-mm noc not the system noc.

system_mm_noc_bfdcd_clk_src is the source clock for the higher frequency
capable system noc mm.

Maximum frequency for the MM SNOC is 400 MHz.

Fixes: 1664014e ("clk: qcom: gcc-msm8939: Add MSM8939 Generic Clock Controller")
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>