[PATCH] scsi_transport_spi build fix

On alpha:

In file included from drivers/scsi/sym53c8xx_2/sym_glue.h:59,
                 from drivers/scsi/sym53c8xx_2/sym_fw.c:40:
include/scsi/scsi_transport_spi.h:57: error: field `dv_mutex' has incomplete type

Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>