ARM: dts: imx: align SPI NOR node name with dtschema

[ Upstream commit ba9fe460 ]

The node names should be generic and SPI NOR dtschema expects "flash".

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Stable-dep-of: af7d78c9 ("ARM: dts: imx6qdl-kontron-samx6i: fix spi-flash compatible")
Signed-off-by: Sasha Levin <sashal@kernel.org>