linux/kernel: Remove EXT2_FS_XIP for version 4.0.
linux/kernel: Remove EXT2_FS_XIP for version 4.0.

The option has been removed in torvalds/linux@6cd176a and thus we
shouldn't try to set it for kernel version 4.

Signed-off-by: aszlig <ee1aa092358634f9c53f01b5a783726c9e21b35a@redmoonstudios.org>

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