Some boards still use xstr(). Replace remaining occurrences
of xstr() by commonly used __stringify().
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Add common code for o2dnt and o2dnt2 based boards and add different
board configuration files for O2D, O2I, O2DNT2, O2D300, O2MNT and
O3DNT boards.
Signed-off-by: Anatolij Gustschin <agust@denx.de>