Pass di to one more call to PIDL_dissect_uint8().

The case for type "char" wasn't fixed.

Change-Id: Ia745263cd4d11a3c00b1ecc72e044f4e404da283
Reviewed-on: https://code.wireshark.org/review/5088
Reviewed-by: Guy Harris <guy@alum.mit.edu>
(cherry picked from commit f2269b4f37f7c3becf7722a5634175f2a3418f54)
Reviewed-on: https://code.wireshark.org/review/5089