Add the device nodes for all MSIOF SPI controllers.

Based on several similar patches of the R8A7796 device tree
by Geert Uytterhoeven <geert+renesas@glider.be>
and Simon Horman <horms+renesas@verge.net.au>.
Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[geert: Use numerical power domain indices for initial r8a77965.dtsi]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>