MIPS: Kconfig: optimize gcc -march and -mtune setup

Move setup of -march to arch/mips/Makefile and follow the design on ARM.
Also add a possibility to chose specific CPU tune options.

Signed-off-by: Wills Wang <wills.wang@live.com>
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 7f7e258..388e4c0 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -43,6 +43,7 @@
 	select SUPPORTS_CPU_MIPS32_R1
 	select SUPPORTS_CPU_MIPS32_R2
 	select SYS_MIPS_CACHE_INIT_RAM_LOAD
+	select MIPS_TUNE_4KC
 
 config TARGET_PB1X00
 	bool "Support pb1x00"
@@ -50,7 +51,7 @@
 	select SUPPORTS_CPU_MIPS32_R1
 	select SUPPORTS_CPU_MIPS32_R2
 	select SYS_MIPS_CACHE_INIT_RAM_LOAD
-
+	select MIPS_TUNE_4KC
 
 endchoice
 
@@ -174,6 +175,15 @@
 	bool
 	default y if CPU_MIPS64_R1 || CPU_MIPS64_R2
 
+config MIPS_TUNE_4KC
+	bool
+
+config MIPS_TUNE_14KC
+	bool
+
+config MIPS_TUNE_24KC
+	bool
+
 config 32BIT
 	bool