drivers/rtc/rtc-s3c.c: fix initialization failure without rtc source clock

Fix unconditional initialization failure on non-exynos3250 SoCs.

Commit df9e26d0 ("rtc: s3c: add support for RTC of Exynos3250 SoC")
introduced rtc source clock support, but also added initialization
failure on SoCs, which doesn't need such clock.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-s3c.c

@@ -535,13 +535,15 @@ static int s3c_rtc_probe(struct platform_device *pdev)
 	}
 	clk_prepare_enable(info->rtc_clk);
 
-	info->rtc_src_clk = devm_clk_get(&pdev->dev, "rtc_src");
-	if (IS_ERR(info->rtc_src_clk)) {
-		dev_err(&pdev->dev, "failed to find rtc source clock\n");
-		return PTR_ERR(info->rtc_src_clk);
+	if (info->data->needs_src_clk) {
+		info->rtc_src_clk = devm_clk_get(&pdev->dev, "rtc_src");
+		if (IS_ERR(info->rtc_src_clk)) {
+			dev_err(&pdev->dev,
+				"failed to find rtc source clock\n");
+			return PTR_ERR(info->rtc_src_clk);
+		}
+		clk_prepare_enable(info->rtc_src_clk);
 	}
-	clk_prepare_enable(info->rtc_src_clk);
-
 
 	/* check to see if everything is setup correctly */
 	if (info->data->enable)