clk: renesas: r8a779f0: Add I2C clocks

Add the module clocks used by the I2C Bus Interfaces on the Renesas
R-Car S4-8 (R8A779F0) SoC.

Extracted from a larger patch in the BSP by LUU HOAI.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/e4dcee5f6f521dccd7ac7f2fb6c86cfe4a24d032.1643898820.git.geert+renesas@glider.be