Fix the last two CFI callback prototype mismatches

There was the series from me a year ago which fixed most of the
callback vs implementation prototype mismatches. It was based on
running the CFI-enabled kernel (in permissive mode -- warning
instead of panic) and performing a full ZTS cycle, and then fixing
all of the problems caught by CFI.
Now, Clang 16-dev has new warning flag, -Wcast-function-type-strict,
which detect such mismatches at compile-time. It allows to find the
remaining issues missed by the first series.
There are only two of them left: one for the
secpolicy_vnode_setattr() callback and one for taskq_dispatch().
The fix is easy, since they are not used anywhere else.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Closes #14207

module/os/linux/zfs/zfs_acl.c

@@ -2788,7 +2788,7 @@ zfs_zaccess_rwx(znode_t *zp, mode_t mode, int flags, cred_t *cr,
  * Access function for secpolicy_vnode_setattr
  */
 int
-zfs_zaccess_unix(znode_t *zp, mode_t mode, cred_t *cr)
+zfs_zaccess_unix(void *zp, int mode, cred_t *cr)
 {
 	int v4_mode = zfs_unix_to_v4(mode >> 6);
 

module/os/linux/zfs/zfs_vnops_os.c

@@ -2186,7 +2186,7 @@ top:
 			vap->va_mask &= ~trim_mask;
 		}
 		err = secpolicy_vnode_setattr(cr, ip, vap, &oldva, flags,
-		    (int (*)(void *, int, cred_t *))zfs_zaccess_unix, zp);
+		    zfs_zaccess_unix, zp);
 		if (err)
 			goto out3;