[SCSI] sd, sym53c8xx: Remove warnings after vsprintf %pV introducation.

GCC warns about empty printf format strings, and after
the addition of %pV these existing such cases in the
scsi driver layer were exposed enough for the compiler
to start seeing them.

Based almost entirely upon a patch by Joe Perches.

[jejb: fix up sym53c8xx msg]
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>