xtensa: fix wrong extern declaration renamed in code using it

The variable ccount_nsec has been renamed to nsec_per_ccount
in arch/xtensa/kernel/time.c in 2b8aea74 (2007-08-05),
but the fix failed to rename the variable in
arch/xtensa/include/asm/timex.h as well.
Signed-off-by: Oskar Schirmer <os@emlix.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

arch/xtensa/include/asm/timex.h

@@ -39,9 +39,9 @@
 
 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
 extern unsigned long ccount_per_jiffy;
-extern unsigned long ccount_nsec;
+extern unsigned long nsec_per_ccount;
 #define CCOUNT_PER_JIFFY ccount_per_jiffy
-#define NSEC_PER_CCOUNT  ccount_nsec
+#define NSEC_PER_CCOUNT  nsec_per_ccount
 #else
 #define CCOUNT_PER_JIFFY (CONFIG_XTENSA_CPU_CLOCK*(1000000UL/HZ))
 #define NSEC_PER_CCOUNT (1000UL / CONFIG_XTENSA_CPU_CLOCK)