85xx, 86xx: Add common board_add_ram_info()

Previously, 85xx and 86xx boards would display DRAM information on
bootup such as:

...
I2C:   ready
DRAM:
Memory controller interleaving enabled: Bank interleaving!
 2 GB
FLASH: 256 MB
...

This patch moves the printing of the DRAM controller configuration to a
common board_add_ram_info() function which prints out DDR type, width,
CAS latency, and ECC mode.  It also makes the DDR interleaving
information print out in a more sane manner:

...
I2C:   ready
DRAM:   2 GB (DDR2, 64-bit, CL=4, ECC on)
       DDR Controller Interleaving Mode: bank
FLASH: 256 MB
...

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>