clk: rockchip: fix issues in the mmc-phase clock

The review for the new inverter clock type uncovered some issues (missing
headers and name handling) that are also present in the mmc-phase clock
type, I got (to much) inspiration from. Fix these there too.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>