[U-Boot] [PATCH] Replace references to extern console_buffer with a function call

[Peter Tyser <ptyser@xes-inc.com>]

> what is the purpose of this patch? As far as I can see we gain
> nothing, but we lose on memory footpint.  I guess there is some
> problem you're trying to fix, but you did not mention it?

I've added a basic "debug serial console" which relies on this patch.
The debug console is a simple command prompt which allows the user to
issue commands before relocating to SDRAM.  We've found this feature
very useful for operations such as initially programming SPD data,
debugging hardware issues (SDRAM/I2C).  I'll submit the debug console
patches shortly.

I'm not sure if the debug console will be accepted to mainline, but I
think this patch alone is an improvement over the current implementation
of using a global string and multiple external console_buffer
references.  I've always thought global variables should be avoided if
there is a reasonable alternative

Best,
Peter