MIPS: Loongson1B: use common clock infrastructure instead of private APIs

Use common clock infrastructure instead of private APIs.
1. Enable COMMON_CLK in the Kconfig.
2. Remove private clock APIs, which are replaced by the code in
   drivers/clk/clk-ls1x.c.
3. Modify header file for drivers/clk/clk-ls1x.c.

Signed-off-by: Kelvin Cheung <keguang.zhang@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/4431
Signed-off-by: John Crispin <blogic@openwrt.org>
diff --git a/arch/mips/loongson1/Kconfig b/arch/mips/loongson1/Kconfig
index a9a14d6..fbf75f6 100644
--- a/arch/mips/loongson1/Kconfig
+++ b/arch/mips/loongson1/Kconfig
@@ -15,7 +15,7 @@
 	select SYS_SUPPORTS_LITTLE_ENDIAN
 	select SYS_SUPPORTS_HIGHMEM
 	select SYS_HAS_EARLY_PRINTK
-	select HAVE_CLK
+	select COMMON_CLK
 
 endchoice