mips: remove redundant macro mc146818_decode_year

The mc146818_decode_year macro is used only in mc146818_get_cmos_time(),
which in turn is called only in
	arch/mips/loongson2ef/common/time.c
and
	arch/mips/mti-malta/malta-time.c
so on mach-jazz it is unused and can be removed. On other platforms it
is defined in the same way, so it can be safely folded into
mc146818_get_cmos_time().

Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/include/asm/mach-generic/mc146818rtc.h

@@ -29,8 +29,4 @@ static inline void CMOS_WRITE(unsigned char data, unsigned long addr)
 
 #define RTC_ALWAYS_BCD	0
 
-#ifndef mc146818_decode_year
-#define mc146818_decode_year(year) ((year) < 70 ? (year) + 2000 : (year) + 1900)
-#endif
-
 #endif /* __ASM_MACH_GENERIC_MC146818RTC_H */

arch/mips/include/asm/mach-jazz/mc146818rtc.h

@@ -33,6 +33,4 @@ static inline void CMOS_WRITE(unsigned char data, unsigned long addr)
 
 #define RTC_ALWAYS_BCD	0
 
-#define mc146818_decode_year(year) ((year) + 1980)
-
 #endif /* __ASM_MACH_JAZZ_MC146818RTC_H */

arch/mips/include/asm/mach-malta/mc146818rtc.h

@@ -31,6 +31,4 @@ static inline void CMOS_WRITE(unsigned char data, unsigned long addr)
 
 #define RTC_ALWAYS_BCD	0
 
-#define mc146818_decode_year(year) ((year) < 70 ? (year) + 2000 : (year) + 1900)
-
 #endif /* __ASM_MACH_MALTA_MC146818RTC_H */

arch/mips/include/asm/mc146818-time.h

@@ -37,7 +37,10 @@ static inline time64_t mc146818_get_cmos_time(void)
 		year = bcd2bin(year);
 	}
 	spin_unlock_irqrestore(&rtc_lock, flags);
-	year = mc146818_decode_year(year);
+	if (year < 70)
+		year += 2000;
+	else
+		year += 1900;
 
 	return mktime64(year, mon, day, hour, min, sec);
 }