drivers/scsi/osd/osd_uld.c: use ida_simple_get() to handle id

drivers/scsi/osd/osd_uld.c: use ida_simple_get() to handle id

This does involve additional use of the spin lock in idr.c.  Is this an
issue?

Also, some error mangling was needed to keep the interface the same.  Does
this matter or can we return -ENOSPC instead of -EBUSY?

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>