libpdbg: Remove unused error code
libpdbg: Remove unused error code

Signed-off-by: Rashmica Gupta <7c7908f246e3c843a2f4c2e4e52ed15aa16cad0a@gmail.com>
Reviewed-by: Nicholas Piggin <24829078df5003d9dd1dd871ca2aeb0b1cf95ef4@gmail.com>

open-power/pdbg,open-power/pdbg,open-power/pdbg