Revert "arm64: dts: Add dts files to enable ION on Hi6220 SoC."

This reverts commit 59dfafd0

Mark Brown reports that the dts file should not be accepted at this time
as it is not following the convention that has been agreed on for the
ion drivers.

Reported-by: Mark Brown <broonie@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Chen Feng <puck.chen@hisilicon.com>
Cc: Yu Dongbin <yudongbin@hisilicon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>