ARM: dts: r9a06g032: Use r9a06g032-sysctrl binding definitions

Replace the hardcoded clock indices by R9A06G032_CLK_* symbols.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>