scsi: sym53c8xx: Avoid undefined behaviour

On parisc I see this UBSAN warning with a sym53c896:

 UBSAN: Undefined behaviour in ./drivers/scsi/sym53c8xx_2/sym_hipd.c:762:24
 index -1903078336 is out of range for type 'u32 [7]'

Avoid this warning by switching to div64_ul().

[mkp: fix typo]
Signed-off-by: NHelge Deller <deller@gmx.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/sym53c8xx_2/sym_hipd.c

@@ -759,7 +759,7 @@ static int sym_prepare_setting(struct Scsi_Host *shost, struct sym_hcb *np, stru
 	/*
 	 * Maximum synchronous period factor supported by the chip.
 	 */
-	period = (11 * div_10M[np->clock_divn - 1]) / (4 * np->clock_khz);
+	period = div64_ul(11 * div_10M[np->clock_divn - 1], 4 * np->clock_khz);
 	np->maxsync = period > 2540 ? 254 : period / 10;
 
 	/*