scsi: sim710: Remove unused variable 'err' from sim710_init()

scsi: sim710: Remove unused variable 'err' from sim710_init()

Take the opportunity to rework the comment a little.

Fixes the following W=1 kernel build warning(s):

 drivers/scsi/sim710.c: In function ‘sim710_init’:
 drivers/scsi/sim710.c:216:6: warning: variable ‘err’ set but not used [-Wunused-but-set-variable]

Link: https://lore.kernel.org/r/20210317091125.2910058-6-lee.jones@linaro.org
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Richard Hirst <richard@sleepie.demon.co.uk>
Cc: c by <James.Bottomley@SteelEye.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>