MIPS: BCM63xx: CLK: Add dummy clk_{set,round}_rate() functions

Several drivers use the clk_{set,round}_rate() functions
that need to be defined in the platform's clock code.
The Broadcom BCM63xx platform hardcodes the clock rate so
we create new clk_{set,round}_rate() functions
which just return 0 like those in include/linux/clk.h
for the common clock framework do.

Also fixes the following build problem on a randconfig:
drivers/built-in.o: In function `nop_usb_xceiv_probe':
phy-nop.c:(.text+0x3ec26c): undefined reference to `clk_set_rate'
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Acked-by: Steven J. Hill <Steven.Hill@imgtec.com>
Acked-by: Florian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5580/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/bcm63xx/clk.c

@@ -318,6 +318,18 @@ unsigned long clk_get_rate(struct clk *clk)
 
 EXPORT_SYMBOL(clk_get_rate);
 
+int clk_set_rate(struct clk *clk, unsigned long rate)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(clk_set_rate);
+
+long clk_round_rate(struct clk *clk, unsigned long rate)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(clk_round_rate);
+
 struct clk *clk_get(struct device *dev, const char *id)
 {
 	if (!strcmp(id, "enet0"))