ARM: 7090/1: CACHE-L2X0: filter start address can be 0 and is often 0

this patch fixes the error in Rob Herring's
ARM: 7009/1: l2x0: Add OF based initialization
http://www.spinics.net/lists/arm-kernel/msg131123.html
it has been in rmk/for-next with commit 41c86ff5b

Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Acked-by: Rob Herring <robherring2@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/cache-l2x0.c

@@ -437,7 +437,7 @@ static void __init pl310_of_setup(const struct device_node *np,
 
 	of_property_read_u32_array(np, "arm,filter-ranges",
 				   filter, ARRAY_SIZE(filter));
-	if (filter[0] && filter[1]) {
+	if (filter[1]) {
 		writel_relaxed(ALIGN(filter[0] + filter[1], SZ_1M),
 			       l2x0_base + L2X0_ADDR_FILTER_END);
 		writel_relaxed((filter[0] & ~(SZ_1M - 1)) | L2X0_ADDR_FILTER_EN,