dt-bindings: arm: fsl: Fix bindings for APF28Dev board

Adjust the compatibles for the APF28Dev board in order to fix the
dtbs_check warning:

  DTC_CHK arch/arm/boot/dts/imx28-apf28dev.dtb
/home/stefanw/torvalds/arch/arm/boot/dts/imx28-apf28dev.dtb: /: compatible:
  oneOf' conditional failed, one must be fixed:
  ['armadeus,imx28-apf28dev', 'armadeus,imx28-apf28', 'fsl,imx28'] is too long
  ['armadeus,imx28-apf28dev', 'armadeus,imx28-apf28', 'fsl,imx28'] is too short
  ...

Fixes: 3d735471 ("dt-bindings: arm: Document Armadeus SoM and Dev boards devicetree binding")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>