clk: qcom: mdss: add support for dynamic refresh on DSI 14nm PLL

Add CLK_SET_RATE_NO_REPARENT flag for the software mux clocks in
DSI 14nm PLL driver which is needed for dynamic refresh feature.

Change-Id: I581e8863abb6c2b46263cac83d115c2a3dd8796c
Signed-off-by: Ritesh Kumar <riteshk@codeaurora.org>