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 <[e-mail]>
[geert: Manual reference]
Signed-off-by: Geert Uytterhoeven <[e-mail]>
Reviewed-by: Yoshihiro Shimoda <[e-mail]>
Link: https://lore.kernel.org/r/d61cf[e-mail]

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

···
 #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