clk: renesas: rzg2l: Use %x format specifier to print CLK_ON_R()

Use the %x format specifier to print CLK_ON_R().  This makes debugging
easier as the value printed will be hexadecimal like in the hardware
manual.  Along with it add "0x" in front of the printed value.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20231010132701.1658737-2-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>