XauDisposeAuth: remove void casts from functions that return void
We rely on having included headers with proper prototypes to know that these functions are declared to return void instead of adding casts to paper over missing prototypes.
Clears warnings from gcc 14.1:
AuDispose.c: In function ‘XauDisposeAuth’:
AuDispose.c:42:13: warning: useless cast to type ‘void’ [-Wuseless-cast]
42 | (void) explicit_bzero (auth->data, auth->data_length);
| ^
AuDispose.c:48:13: warning: useless cast to type ‘void’ [-Wuseless-cast]
48 | (void) free (auth->data);
| ^
Signed-off-by: Alan Coopersmith