scsi: sd: Fix function name in header

scsi: sd: Fix function name in header

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

 drivers/scsi/sd.c:1537: warning: expecting prototype for sd_ioctl(). Prototype was for sd_ioctl_common() instead

Link: https://lore.kernel.org/r/20210317091230.2912389-7-lee.jones@linaro.org
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Drew Eckhardt <drew@colorado.edu>
Cc: Eric Youngdale <eric@andante.org>
Cc: Jirka Hanika <geo@ff.cuni.cz>
Cc: Richard Gooch <rgooch@atnf.csiro.au>
Cc: Torben Mathiasen <tmm@image.dk>
Cc: Alex Davis <letmein@erols.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: willy@debian.org
Cc: Kurt Garloff <garloff@suse.de>
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>