Remove unused variable in delay.c

Index: linux/arch/x86_64/lib/delay.c
===================================================================
--- linux.orig/arch/x86_64/lib/delay.c
+++ linux/arch/x86_64/lib/delay.c
@@ -18,8 +18,6 @@
 #include <asm/smp.h>
 #endif
 
-int x86_udelay_tsc = 0;		/* Delay via TSC */
-
 int read_current_timer(unsigned long *timer_value)
 {
 	rdtscll(*timer_value);