csky: Fixup do_page_fault parent irq status

We must succeed parent's context irq status in page fault handler.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>

arch/csky/kernel/entry.S

@@ -42,7 +42,7 @@ ENTRY(csky_pagefault)
 	SAVE_ALL 0
 	zero_fp
 	context_tracking
-	psrset  ee, ie
+	psrset  ee
 	mov     a0, sp
 	jbsr    do_page_fault
 	jmpi    ret_from_exception

arch/csky/mm/fault.c

@@ -143,6 +143,10 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
 		return;
 	}
 
+	/* Enable interrupts if they were enabled in the parent context. */
+	if (likely(regs->sr & BIT(6)))
+		local_irq_enable();
+
 	/*
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..