MIPS: Remove cpu_has_6k_cache and cpu_has_8k_cache in cpu_cache_init()

Since commit 02cf2119 ("Cleanup the mess in cpu_cache_init."),
cpu_has_6k_cache and cpu_has_8k_cache have no user, r6k_cache_init()
and r8k_cache_init() are not defined for over 15 years, just remove
them.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/include/asm/cpu-features.h

@@ -115,8 +115,6 @@
 #ifndef cpu_has_3k_cache
 #define cpu_has_3k_cache	__isa_lt_and_opt(1, MIPS_CPU_3K_CACHE)
 #endif
-#define cpu_has_6k_cache	0
-#define cpu_has_8k_cache	0
 #ifndef cpu_has_4k_cache
 #define cpu_has_4k_cache	__isa_ge_or_opt(1, MIPS_CPU_4K_CACHE)
 #endif

arch/mips/mm/cache.c

@@ -188,21 +188,11 @@ void cpu_cache_init(void)
 
 		r3k_cache_init();
 	}
-	if (cpu_has_6k_cache) {
-		extern void __weak r6k_cache_init(void);
-
-		r6k_cache_init();
-	}
 	if (cpu_has_4k_cache) {
 		extern void __weak r4k_cache_init(void);
 
 		r4k_cache_init();
 	}
-	if (cpu_has_8k_cache) {
-		extern void __weak r8k_cache_init(void);
-
-		r8k_cache_init();
-	}
 	if (cpu_has_tx39_cache) {
 		extern void __weak tx39_cache_init(void);