The Colombus defconfig settings are missing a number of settings for recently
added features, because we did not know exactly how things were hooked up.

Maxime Ripard has run various tests to get us the necessary details, this
commit updates the defconfig with this info.

This commit also updates the dram clk and zq values with values verified
by Maxime to be the ones used by the original firmware for this board.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>