arch/powerpc/sysdev/fsl_rio.c: correct IECSR register clear value

This bug causes the IECSR register clear failure.  In this case, the RETE
(retry error threshold exceeded) interrupt will be generated and cannot be
cleared.  So the related ISR may be called persistently.

The RETE bit in IECSR is cleared by writing a 1 to it.
Signed-off-by: Liu Gang <Gang.Liu@freescale.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/sysdev/fsl_rio.c

@@ -54,6 +54,7 @@
 #define ODSR_CLEAR		0x1c00
 #define LTLEECSR_ENABLE_ALL	0xFFC000FC
 #define ESCSR_CLEAR		0x07120204
+#define IECSR_CLEAR		0x80000000
 
 #define RIO_PORT1_EDCSR		0x0640
 #define RIO_PORT2_EDCSR		0x0680
@@ -1089,11 +1090,11 @@ static void port_error_handler(struct rio_mport *port, int offset)
 
 	if (offset == 0) {
 		out_be32((u32 *)(rio_regs_win + RIO_PORT1_EDCSR), 0);
-		out_be32((u32 *)(rio_regs_win + RIO_PORT1_IECSR), 0);
+		out_be32((u32 *)(rio_regs_win + RIO_PORT1_IECSR), IECSR_CLEAR);
 		out_be32((u32 *)(rio_regs_win + RIO_ESCSR), ESCSR_CLEAR);
 	} else {
 		out_be32((u32 *)(rio_regs_win + RIO_PORT2_EDCSR), 0);
-		out_be32((u32 *)(rio_regs_win + RIO_PORT2_IECSR), 0);
+		out_be32((u32 *)(rio_regs_win + RIO_PORT2_IECSR), IECSR_CLEAR);
 		out_be32((u32 *)(rio_regs_win + RIO_PORT2_ESCSR), ESCSR_CLEAR);
 	}
 }