[MIPS] time: Add GT641xx timer0 clockevent driver

And make use of it for Cobalt.  A few others such as the Malta could make
use of it as well.

Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 3ecff5e..61262c5 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -66,6 +66,7 @@
 config MIPS_COBALT
 	bool "Cobalt Server"
 	select CEVT_R4K
+	select CEVT_GT641XX
 	select DMA_NONCOHERENT
 	select HW_HAS_PCI
 	select I8253
@@ -729,6 +730,9 @@
 config BOOT_RAW
 	bool
 
+config CEVT_GT641XX
+	bool
+
 config CEVT_R4K
 	bool