mmc: sdhci-pxav3: fix setting of pdata->clk_delay_cycles

Current code checks "clk_delay_cycles > 0" to know whether the optional
"mrvl,clk_delay_cycles" is set or not. But of_property_read_u32() doesn't
touch clk_delay_cycles if the property is not set. And type of
clk_delay_cycles is u32, so we may always set pdata->clk_delay_cycles as a
random value.

This patch fix this problem by check the return value of of_property_read_u32()
to know whether the optional clk-delay-cycles is set or not.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Cc: <stable@vger.kernel.org> # v3.6+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-pxav3.c

@@ -268,8 +268,8 @@ static struct sdhci_pxa_platdata *pxav3_get_mmc_pdata(struct device *dev)
 	if (!pdata)
 		return NULL;
 
-	of_property_read_u32(np, "mrvl,clk-delay-cycles", &clk_delay_cycles);
-	if (clk_delay_cycles > 0)
+	if (!of_property_read_u32(np, "mrvl,clk-delay-cycles",
+				  &clk_delay_cycles))
 		pdata->clk_delay_cycles = clk_delay_cycles;
 
 	return pdata;