dt-bindings: power: r8a779g0: Add missing A3DUL power domain

Add the power domain index for the A3DUL domain, as described in the
R-Car V4H Series Hardware User's Manual Rev. 0.51 and later.
Signed-off-by: Tam Nguyen <tam.nguyen.xa@renesas.com>
[geert: Manual reference]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/d61cf54b58629a76e007b9505dac7c2beb3b30db.1669740926.git.geert+renesas@glider.be

include/dt-bindings/power/r8a779g0-sysc.h

@@ -38,6 +38,7 @@
 #define R8A779G0_PD_A3VIP2		58
 #define R8A779G0_PD_A3ISP0		60
 #define R8A779G0_PD_A3ISP1		61
+#define R8A779G0_PD_A3DUL		62
 
 /* Always-on power area */
 #define R8A779G0_PD_ALWAYS_ON		64