ARM: S5P: Add USB External Crystal clock definition

Add USB external crystal clock definition Xusbxti to common S5P clock code.
Signed-off-by: NThomas Abraham <thomas.ab@samsung.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NBen Dooks <ben-linux@fluff.org>

arch/arm/plat-s5p/clock.c

@@ -33,6 +33,11 @@ struct clk clk_ext_xtal_mux = {
 	.id		= -1,
 };
 
+struct clk clk_xusbxti = {
+	.name		= "xusbxti",
+	.id		= -1,
+};
+
 static struct clk s5p_clk_27m = {
 	.name		= "clk_27m",
 	.id		= -1,

arch/arm/plat-s5p/include/plat/s5p-clock.h

@@ -23,6 +23,7 @@
 #define clk_fin_vpll clk_ext_xtal_mux
 
 extern struct clk clk_ext_xtal_mux;
+extern struct clk clk_xusbxti;
 extern struct clk clk_48m;
 extern struct clk clk_fout_apll;
 extern struct clk clk_fout_mpll;