alpha: properly define get/set_rtc_time on Marvel/SMP

The marvel_get_rtc_time and marvel_set_rtc_time are static, but they're
available through Marvel's machine vector.
Reported-by: Raúl Porcel <armin76@gentoo.org>
Signed-off-by: Matt Turner <mattst88@gmail.com>

arch/alpha/include/asm/rtc.h

 #ifndef _ALPHA_RTC_H
 #define _ALPHA_RTC_H
 
-#if defined(CONFIG_ALPHA_GENERIC)
+#if defined(CONFIG_ALPHA_MARVEL) && defined(CONFIG_SMP) \
+ || defined(CONFIG_ALPHA_GENERIC)
 # define get_rtc_time		alpha_mv.rtc_get_time
 # define set_rtc_time		alpha_mv.rtc_set_time
-#else
-# if defined(CONFIG_ALPHA_MARVEL) && defined(CONFIG_SMP)
-#  define get_rtc_time		marvel_get_rtc_time
-#  define set_rtc_time		marvel_set_rtc_time
-# endif
 #endif
 
 #include <asm-generic/rtc.h>