[SCSI] gdth: fix ambiguous gdthtable definition

Labeling a variable as __attribute_used__ is ambiguous: it means
__attribute__((unused)) for gcc <3.4 and __attribute__((used)) for gcc >=3.4.
There is no such thing as labeling a variable as __attribute__((used)).  We
assume that we're simply suppressing a warning here if gdthtable[] is declared
but unreferenced.

Acked-by: Achim Leubner <achim_leubner@adaptec.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>