clk: renesas: rzg2l: Support sd clk mux round operation

Currently, determine_rate() is not doing any round operation
and due to this it always selects a lower clock source compared
to the closest higher one.

Support sd clk mux round operation by passing
CLK_MUX_ROUND_CLOSEST flag to clk_mux_determine_rate_flags().

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20220919084110.3065156-1-biju.das.jz@bp.renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>