powerpc/512x: clk: Remove CLK_IS_ROOT

This flag is a no-op now (see commit 47b0eeb3 "clk: Deprecate
CLK_IS_ROOT", 2016-02-02) so remove it.

Cc: Gerhard Sittig <gsi@denx.de>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

arch/powerpc/platforms/512x/clock-commonclk.c

@@ -221,7 +221,7 @@ static bool soc_has_mclk_mux0_canin(void)
 /* convenience wrappers around the common clk API */
 static inline struct clk *mpc512x_clk_fixed(const char *name, int rate)
 {
-	return clk_register_fixed_rate(NULL, name, NULL, CLK_IS_ROOT, rate);
+	return clk_register_fixed_rate(NULL, name, NULL, 0, rate);
 }
 
 static inline struct clk *mpc512x_clk_factor(