sparc32: Pass task_struct to schedule_tail() in ret_from_fork

We have to pass task_struct of previous process to function
schedule_tail(). Currently in ret_from_fork previous thread_info
is passed:

switch_to: mov %g6, %g3 /* previous thread_info in g6 */

ret_from_fork: call    schedule_tail
                mov    %g3, %o0 /* previous thread_info is passed */

void schedule_tail(struct task_struct *prev);
Signed-off-by: NTkhai Kirill <tkhai@yandex.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc/kernel/entry.S

@@ -1283,7 +1283,7 @@ linux_syscall_trace:
 	.globl	ret_from_fork
 ret_from_fork:
 	call	schedule_tail
-	 mov	%g3, %o0
+	 ld	[%g3 + TI_TASK], %o0
 	b	ret_sys_call
 	 ld	[%sp + STACKFRAME_SZ + PT_I0], %o0