soc: renesas: r8a77970-sysc: fix power area parents

According to the figure 9.2(b) of the R-Car Series, 3rd Generation User’s
Manual: Hardware Rev. 0.80 the A2IRn and A2SCn power areas in R8A77970 have
the A3IR area as a parent, thus the SYSC driver has those parents wrong...

Fixes: bab9b2a7 ("soc: renesas: rcar-sysc: add R8A77970 support")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>