Clang 15 from Fedora 37 complains:

 ../libdecnumber/dpd/decimal64.c:620:8: error: variable 'n' set but
 not used [-Werror,-Wunused-but-set-variable]
   Int  n;                     /* output bunch counter */
        ^
 1 error generated.

Remove the unused variable to silence the compiler warning.

Message-Id: <20221110131112.104283-1-thuth@redhat.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>