MIPS: add tune for MIPS 34kc

Add tune Kconfig option for MIPS 34kc.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index abaeaf0..a929452 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -228,6 +228,9 @@
 config MIPS_TUNE_24KC
 	bool
 
+config MIPS_TUNE_34KC
+	bool
+
 config MIPS_TUNE_74KC
 	bool