ARM: 7608/1: l2x0: Only set .set_debug on PL310 r3p0 and earlier

PL310 errata work-arounds using .set_debug function are only needed on
r3p0 and earlier, so check the rev and only set .set_debug on older revs.

Avoiding debug register accesses fixes aborts on non-secure platforms
like highbank. It is assumed that non-secure platforms needing these
work-arounds have already implemented .set_debug with secure monitor
calls.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/cache-l2x0.c

@@ -352,7 +352,8 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
 		/* Unmapped register. */
 		sync_reg_offset = L2X0_DUMMY_REG;
 #endif
-		outer_cache.set_debug = pl310_set_debug;
+		if ((cache_id & L2X0_CACHE_ID_RTL_MASK) <= L2X0_CACHE_ID_RTL_R3P0)
+			outer_cache.set_debug = pl310_set_debug;
 		break;
 	case L2X0_CACHE_ID_PART_L210:
 		ways = (aux >> 13) & 0xf;