ARM: dts: aspeed: align SPI node name with dtschema

The node names should be generic and DT schema expects certain pattern.

Link: https://lore.kernel.org/r/20220830180344.15657-1-krzysztof.kozlowski@linaro.org


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>