drivers/scsi/ch.c: don't use vprintk as macro

It's an exported symbol of kernel/printk.c

Rename vprintk and dprintk macros to more common VPRINTK and DPRINTK
Add do { } while(0) around macros
Add level to VPRINTK so KERN_CONT can be used a couple of times.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>