checkstyle9: Allow a space between "*" and _*restrict

Before the change, we would get errors like this:

ERROR: "foo * bar" should be "foo *bar"
#369: FILE: foobar.c:369:
+barbaz(char * __restrict s,

Reviewed by: des, imp
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D44911