sparc: fix debug support

Declare and use the correct registers to define a stack frame.

Change-Id: Ice3ba8f8715313a715f6b1cb553a6883541f5cc4
Reviewed-on: https://review.haiku-os.org/c/1327
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>

sparc: add defines and minimum set of required files

Gets the stage0 bootstrap to run.
Imlementation is probably nonsense at this point.

Change-Id: I10876efbb54314b864c0ad951152757cdb2fd366
Reviewed-on: https://review.haiku-os.org/c/1061
Reviewed-by: waddlesplash <waddlesplash@gmail.com>