powerpc/mpc5200: Don't touch pipelining for MPC5200B

MPC5200 needs to have pipelining disabled for ATA to work. MPC5200B does not.
So, for the latter, don't touch the original setting from the bootloader.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

arch/powerpc/platforms/52xx/mpc52xx_common.c

@@ -99,10 +99,13 @@ mpc5200_setup_xlb_arbiter(void)
 	out_be32(&xlb->master_pri_enable, 0xff);
 	out_be32(&xlb->master_priority, 0x11111111);
 
-	/* Disable XLB pipelining
+	/*
+	 * Disable XLB pipelining
 	 * (cfr errate 292. We could do this only just before ATA PIO
 	 *  transaction and re-enable it afterwards ...)
+	 * Not needed on MPC5200B.
 	 */
+	if ((mfspr(SPRN_SVR) & MPC5200_SVR_MASK) == MPC5200_SVR)
 		out_be32(&xlb->config, in_be32(&xlb->config) | MPC52xx_XLB_CFG_PLDIS);
 
 	iounmap(xlb);