eco32: pgtable: add bit for noncached pages

Since there are no cache architecture defined for eco32 yet,
this only serves as a placeholder for the bit that should mark
pages as non-cached.

Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
eco32: add dma support

This should be considered as a stub implementation since there
are no cache architecture defined for eco32 yet.

Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
eco32: update eco32_generic.dts to reflect eco32-0.22

Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>