Umon command line reached in BBB

[Jarielle Catbagan]

Going off of the discussion that I had with Ed in regards to getting a
fully internal SRAM mapped Umon image to work before proceeding to
implement the DDR3 configuration to have the RAM used by Umon mapped
there, I went ahead and started working on it.

I configured the Umon image to be fully mapped within the internal
SRAM of the AM335x (i.e. BOOTROMBASE/BOOTRAMBASE defined to be within
the internal SRAM with their corresponding lengths ensured to not
overlap each other and to not exceed the SRAM boundaries), and then
enabled INCLUDE_MEMCMDS by setting it to test the DM and PM commands.
I know that these commands will not work properly given the fact that
DDR3 is not set up yet, but just wanted to see if some command
execution is possible.

I then proceeded to build the image and then booted the image on the
BBB via UART.  Once booted, the Umon command line was presented and
did some command execution testing.  Nothing works properly as of
right now, but now that I am able to reach the Umon command line I can
now proceed to getting the other functions implemented.

My results of getting the Umon command line on the BBB can be found in
the screen capture provided below.

https://drive.google.com/file/d/0B_44Dkqbmn75TjQwZjJaczNJYk0/view?usp=sharing