clk/efm32gg: fix dt init prototype

Since commit 54196ccbe0 (of: consolidate linker section OF match table
declarations) which went into 3.16-rc1 the following compiler warning is
generated:

	In file included from drivers/clk/clk-efm32gg.c:12:0: include/linux/of.h:772:20:
	warning: comparison of distinct pointer types lacks a cast [enabled by default]
		.data = (fn == (fn_type)NULL) ? fn : fn  }
			    ^
	include/linux/of.h:785:3: note: in expansion of macro '_OF_DECLARE'
	   _OF_DECLARE(table, name, compat, fn, of_init_fn_1)
	   ^
	include/linux/clk-provider.h:545:42: note: in expansion of macro 'OF_DECLARE_1'
	 #define CLK_OF_DECLARE(name, compat, fn) OF_DECLARE_1(clk, name, compat, fn)
						  ^
	drivers/clk/clk-efm32gg.c:81:1: note: in expansion of macro 'CLK_OF_DECLARE'
	 CLK_OF_DECLARE(efm32ggcmu, "efm32gg,cmu", efm32gg_cmu_init);
	 ^

Fix it by making efm32gg_cmu_init return void.

Cc: Rob Herring <robh@kernel.org>
Reported-by: Bryan Hundven <bryanhundven@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/clk-efm32gg.c

@@ -22,7 +22,7 @@ static struct clk_onecell_data clk_data = {
 	.clk_num = ARRAY_SIZE(clk),
 };
 
-static int __init efm32gg_cmu_init(struct device_node *np)
+static void __init efm32gg_cmu_init(struct device_node *np)
 {
 	int i;
 	void __iomem *base;
@@ -33,7 +33,7 @@ static int __init efm32gg_cmu_init(struct device_node *np)
 	base = of_iomap(np, 0);
 	if (!base) {
 		pr_warn("Failed to map address range for efm32gg,cmu node\n");
-		return -EADDRNOTAVAIL;
+		return;
 	}
 
 	clk[clk_HFXO] = clk_register_fixed_rate(NULL, "HFXO", NULL,
@@ -76,6 +76,6 @@ static int __init efm32gg_cmu_init(struct device_node *np)
 	clk[clk_HFPERCLKDAC0] = clk_register_gate(NULL, "HFPERCLK.DAC0",
 			"HFXO", 0, base + CMU_HFPERCLKEN0, 17, 0, NULL);
 
-	return of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
+	of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
 }
 CLK_OF_DECLARE(efm32ggcmu, "efm32gg,cmu", efm32gg_cmu_init);