dt-bindings: clock: r9a07g044-cpg: Add entry for P0_DIV2 core clock

Add P0_DIV2 core clock required for CANFD module. CANFD core clock is
sourced from P0_DIV2 referenced from HW manual Rev.0.50.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20210719143811.2135-4-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

include/dt-bindings/clock/r9a07g044-cpg.h

@@ -30,6 +30,7 @@
 #define R9A07G044_CLK_P2		19
 #define R9A07G044_CLK_AT		20
 #define R9A07G044_OSCCLK		21
+#define R9A07G044_CLK_P0_DIV2		22
 
 /* R9A07G044 Module Clocks */
 #define R9A07G044_CA55_SCLK		0