dt-bindings: mmc: renesas,sdhi: Add R-Car Gen4 clock requirements

The patch enabling generic Gen4 support forgot to add the clock
requirements which are the same as for Gen3. Update the binding.

Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20220608122344.3431-1-wsa+renesas@sang-engineering.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>