xen/arm: ffa: fix bind/unbind notification

The notification bitmask is in passed in the FF-A ABI in two 32-bit
registers w3 and w4. The lower 32-bits should go in w3 and the higher in
w4. These two registers has unfortunately been swapped for
FFA_NOTIFICATION_BIND and FFA_NOTIFICATION_UNBIND in the FF-A mediator.
So fix that by using the correct registers.

Fixes: b490f470f5 ("xen/arm: ffa: support notification")
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Relese-Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>

xen/arch/arm/tee/ffa_notif.c

@@ -40,8 +40,8 @@ int ffa_handle_notification_bind(struct cpu_user_regs *regs)
      * We only support notifications from SP so no need to check the sender
      * endpoint ID, the SPMC will take care of that for us.
      */
-    return ffa_simple_call(FFA_NOTIFICATION_BIND, src_dst, flags, bitmap_hi,
-                           bitmap_lo);
+    return ffa_simple_call(FFA_NOTIFICATION_BIND, src_dst, flags, bitmap_lo,
+                           bitmap_hi);
 }
 
 int ffa_handle_notification_unbind(struct cpu_user_regs *regs)
@@ -61,8 +61,8 @@ int ffa_handle_notification_unbind(struct cpu_user_regs *regs)
      * We only support notifications from SP so no need to check the
      * destination endpoint ID, the SPMC will take care of that for us.
      */
-    return  ffa_simple_call(FFA_NOTIFICATION_UNBIND, src_dst, 0, bitmap_hi,
-                            bitmap_lo);
+    return  ffa_simple_call(FFA_NOTIFICATION_UNBIND, src_dst, 0, bitmap_lo,
+                            bitmap_hi);
 }
 
 void ffa_handle_notification_info_get(struct cpu_user_regs *regs)