sparc: make proces_ver_nack a bit more readable

Impact: clean up

The code in process_ver_nack is a little obfuscated. This change
makes it a bit more readable by humans. It removes the complex
if statement and replaces it with a cleaner flow of control.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>