clk: renesas: r8a7796: Add DRIF clock

This patch adds DRIF module clocks for r8a7796 SoC.

Signed-off-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>