arm64: dts: renesas: r8a779g3-sparrow-hawk-fan-pwm: Add missing install target

arm64: dts: renesas: r8a779g3-sparrow-hawk-fan-pwm: Add missing install target

The target to consider the dtbo file for installation is missing, add
it.

Fixes: a719915e76f2 ("arm64: dts: renesas: r8a779g3: Add Retronix R-Car V4H Sparrow Hawk board support")
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Link: https://lore.kernel.org/20250701112612.3957799-2-niklas.soderlund+renesas@ragnatech.se
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>