Input: Convert DeviceIntRec::last to use doubles

Change the last real user of a split integer/fractional co-ordinate
system, DeviceIntRec's last->{valuators,remainder} to just have one set
of doubles.

Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>

include/inputstr.h

@@ -521,8 +521,7 @@ typedef struct _DeviceIntRec {
      * remainder supports acceleration
      */
     struct {
-        int             valuators[MAX_VALUATORS];
-        float           remainder[MAX_VALUATORS];
+        double          valuators[MAX_VALUATORS];
         int             numValuators;
         DeviceIntPtr    slave;
     } last;