xtensa: export ccount_freq

Now that ccount_freq is used in udelay and ndelay it needs to be
exported in order to be available to modules.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/kernel/time.c

@@ -30,6 +30,7 @@
 #include <asm/platform.h>
 
 unsigned long ccount_freq;		/* ccount Hz */
+EXPORT_SYMBOL(ccount_freq);
 
 static cycle_t ccount_read(struct clocksource *cs)
 {