i3200_edac: Add more debug to the driver

Currently, it is not possible to know, when debug is enabled,
if the driver is using 2 DIMMS per channel mode or not. It is
not possible to know the values of the drbs registers, used
to identify the memory rank sizes.

Add debug for both, as it helps to track issues on the driver.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>