mi: don't check for core events in miPointerSetPosition (#53568)

As of 81cfe44b1e, miPointerSetPosition now
returns the screen pointer of the device. This broke floating slave devices,
as soon as a motion event was submitted, miPointerSetPosition returned NULL,
crashing the server.

dev->coreEvents is only false if the device is a floating slave, in which
case it has a sprite.

X.Org Bug 53568 <http://bugs.freedesktop.org/show_bug.cgi?id=53568>

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Keith Packard <keithp@keithp.com>

mi/mipointer.c

@@ -575,7 +575,7 @@ miPointerSetPosition(DeviceIntPtr pDev, int mode, double *screenx,
 
     miPointerPtr pPointer;
 
-    if (!pDev || !pDev->coreEvents)
+    if (!pDev)
         return NULL;
 
     pPointer = MIPOINTER(pDev);