sunxi: Remove bogus uart entry from utoo-p66 dts file

At one point in time the utoo-p66 dts file in the kernel had a bogus
uart entry, and it seems like we synced with the kernel at just the wrong
moment.

This commit removes the bogus uart entry, which breaks booting the utoo-p66
when DM_SERIAL=y.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>