Implement fast-path error code printout for errors with no associated
handler function. This reduces calls to this kmalloc() nonsense in
SPRINTFCAT() already.

Note that the format of output is compatible with the old code, even
if -- exposed like this -- it looks a bit weird. Checkpatch complains
on this one as well.
Signed-off-by: NMarek Vasut <marex@denx.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Horia Geanta <horia.geanta@freescale.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>