Correct a typo in the vin-supply property.  The input supply is
always-on, so this mistake doesn't affect whether the supply is actually
enabled correctly.

Fixes: 4403e123 ("arm64: dts: rockchip: Add devicetree for board roc-rk3308-cc")
Signed-off-by: NJohn Keeping <john@metanate.com>
Link: https://lore.kernel.org/r/20211102182908.3409670-2-john@metanate.comSigned-off-by: NHeiko Stuebner <heiko@sntech.de>