ARM: SAMSUNG: Update default rate for xusbxti clock

The rate of xusbxti clock is set in individual machine files.
The default value should be defined at the clock definition
and individual machine files should modify it if required.

Division by zero in kernel.
[<c0011849>] (unwind_backtrace+0x1/0x9c) from [<c022c663>] (Ldiv0+0x9/0x12)
[<c022c663>] (Ldiv0+0x9/0x12) from [<c001a3c3>] (s3c_setrate_clksrc+0x33/0x78)
[<c001a3c3>] (s3c_setrate_clksrc+0x33/0x78) from [<c0019e67>] (clk_set_rate+0x2f/0x78)

Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/plat-samsung/s5p-clock.c

@@ -37,6 +37,7 @@ struct clk clk_ext_xtal_mux = {
 struct clk clk_xusbxti = {
 	.name		= "xusbxti",
 	.id		= -1,
+	.rate		= 24000000,
 };
 
 struct clk s5p_clk_27m = {