soc: sunxi: sram: Return void from the release function

soc: sunxi: sram: Return void from the release function

There is no point in returning an error here, as the caller can do
nothing about it. In fact, all callers already ignore the return value.

Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220815041248.53268-8-samuel@sholland.org
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>