MIPS: ath79: Use a helper function to get system clock rates

The ath79 platform uses similar code to get the
rate of various clocks during init. Separate the
similar code into a new helper function and use
that to avoid code duplication.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5778/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/ath79/dev-common.c

@@ -81,21 +81,19 @@ static struct platform_device ar933x_uart_device = {
 
 void __init ath79_register_uart(void)
 {
-	struct clk *clk;
+	unsigned long uart_clk_rate;
 
-	clk = clk_get(NULL, "uart");
-	if (IS_ERR(clk))
-		panic("unable to get UART clock, err=%ld", PTR_ERR(clk));
+	uart_clk_rate = ath79_get_sys_clk_rate("uart");
 
 	if (soc_is_ar71xx() ||
 	    soc_is_ar724x() ||
 	    soc_is_ar913x() ||
 	    soc_is_ar934x() ||
 	    soc_is_qca955x()) {
-		ath79_uart_data[0].uartclk = clk_get_rate(clk);
+		ath79_uart_data[0].uartclk = uart_clk_rate;
 		platform_device_register(&ath79_uart_device);
 	} else if (soc_is_ar933x()) {
-		ar933x_uart_data.uartclk = clk_get_rate(clk);
+		ar933x_uart_data.uartclk = uart_clk_rate;
 		platform_device_register(&ar933x_uart_device);
 	} else {
 		BUG();