xfree86: fix readlink call

Misplaced parenthesis caused us to compare the sizeof, not the readlink return
value.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit bd5fe759)
1 job for fix-parens in 4 minutes and 46 seconds (queued for 2 minutes and 24 seconds)
Status Job ID Name Coverage
  Test
passed #29508
job

00:04:46