xtensa: remove platform rtc hooks

platform_get/set_rtc_time() is not implemented by any of the supported
xtensa platforms.  Remove the facility completely.

The initial seconds for xtime come from read_persistent_clock() which
returns just 0 in the generic implementation.  Platforms that sport a
persistent clock can implement this function.

This is needed to implement the ccount as a clock source.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Chris Zankel <chris@zankel.net>

arch/xtensa/include/asm/platform.h

@@ -74,16 +74,5 @@ extern int platform_pcibios_fixup (void);
  */
 extern void platform_calibrate_ccount (void);
 
-/*
- * platform_get_rtc_time returns RTC seconds (returns 0 for no error)
- */
-extern int platform_get_rtc_time(time_t*);
-
-/*
- * platform_set_rtc_time set RTC seconds (returns 0 for no error)
- */
-extern int platform_set_rtc_time(time_t);
-
-
 #endif	/* _XTENSA_PLATFORM_H */