Fix lpfc_parse_bg_err()'s use of do_div()

Fix lpfc_parse_bg_err()'s use of do_div().  It should be passing a 64-bit
variable as the first parameter.  However, since it's only using a 32-bit
variable, it doesn't need to use do_div() at all, but can instead use the
division operator.

This deals with the following warnings:

    CC      drivers/scsi/lpfc/lpfc_scsi.o
  drivers/scsi/lpfc/lpfc_scsi.c: In function 'lpfc_parse_bg_err':
  drivers/scsi/lpfc/lpfc_scsi.c:1397: warning: comparison of distinct pointer types lacks a cast
  drivers/scsi/lpfc/lpfc_scsi.c:1397: warning: right shift count >= width of type
  drivers/scsi/lpfc/lpfc_scsi.c:1397: warning: passing argument 1 of '__div64_32' from incompatible pointer type

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>