scsi: sym53c8xx_2: Fix sizeof() mismatch

An incorrect sizeof() is being used, struct sym_ccb ** is not correct, it
should be struct sym_ccb *. Note that since ** is the same size as * this
is not causing any issues.  Improve this fix by using the idiom
sizeof(*np->ccbh) as this allows one to not even reference the type of the
pointer.

[ Note: this is an ancient 2005 buglet, the sha is from the
  tglx/history repo ]

Link: https://lore.kernel.org/r/20201006110252.536641-1-colin.king@canonical.com
Fixes: 473c67f96e06 ("[PATCH] sym2 version 2.2.0")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Addresses-Coverity: ("Sizeof not portable (SIZEOF_MISMATCH)")