ephyr: enable option -sw-cursor by default in multi-seat mode

Option -seat passed to Xephyr requires -sw-cursor to be passed as well,
otherwise the mouse cursor will remain invisible for the given seat.
This patch takes care of enabling -sw-cursor if -seat is passed.

Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Laércio de Sousa <laerciosousa@sme-mogidascruzes.sp.gov.br>

hw/kdrive/ephyr/ephyrinit.c

@@ -373,6 +373,9 @@ OsVendorInit(void)
 {
     EPHYR_DBG("mark");
 
+    if (SeatId)
+        hostx_use_sw_cursor();
+
     if (hostx_want_host_cursor())
         ephyrFuncs.initCursor = &ephyrCursorInit;