xfree86: Remove unnecessary errno save/restore in xf86ReadInput

When this code was called from SIGIO, saving and restoring errno could
possibly have made sense in some strange environment. Now that this
will not be called from a signal handler, there is no reason to do that.

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

hw/xfree86/common/xf86Events.c

@@ -298,12 +298,9 @@ xf86Wakeup(void *blockData, int err, void *pReadmask)
 static void
 xf86ReadInput(int fd, int ready, void *closure)
 {
-    int errno_save = errno;
     InputInfoPtr pInfo = closure;
 
     pInfo->read_input(pInfo);
-
-    errno = errno_save;
 }
 
 /*