audit: Fix decimal constant description

audit: Fix decimal constant description

Use proper decimal type for comparison with u32.

Compilation warning was introduced by 780a7654 ("audit: Make testing for
a valid loginuid explicit.")

  kernel/auditfilter.c: In function 'audit_data_to_entry':
  kernel/auditfilter.c:426:3: warning: this decimal constant is unsigned only in ISO C90 [enabled by default]
     if ((f->type == AUDIT_LOGINUID) && (f->val == 4294967295)) {

Signed-off-by: Michal Simek <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Eric Paris <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>