suspicious pointer arithmetic in libchk

[Jeff Johnson]

The following is reported by Coverity about misc-test/libchk/classchk.c:

CID 1099432 (#1 of 1): Extra sizeof expression (SIZEOF_MISMATCH)

suspicious_pointer_arithmetic: Adding "vmi_rttip->base_count * 16UL /* sizeof
(struct base_type_info_mem) */" to pointer "(void **)(char
*)vmi_rttip->base_info" of type "void **" is suspicious because adding an
integral value to this pointer automatically scales that value by the size, 8
bytes, of the pointed-to type, "void *". Most likely, the multiplication by
"sizeof (struct base_type_info_mem)" in this expression is extraneous and
should be eliminated.

 977 basetypes = (void **) ((char *) vmi_rttip->base_info) +
 978 (vmi_rttip->base_count * sizeof(struct base_type_info_mem));

I'm not sure it's wrong, but perhaps unnecessarily convoluted given it has
confused the checker. We've cast it to char * to enable the multiply to make
sense, when vmi_rttip->base_info is already type struct base_type_info_mem and
so would scale...