SELinux: policydb.h whitespace, syntax, and other cleanups

This patch changes policydb.h to fix whitespace and syntax issues.  Things that
are fixed may include (does not not have to include)

spaces followed by tabs
spaces used instead of tabs
location of * in pointer declarations

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>