LoongArch: Remove some extern variables in source files

There are declarations of the variable "eentry", "pcpu_handlers[]" and
"exception_handlers[]" in asm/setup.h, the source files already include
this header file directly or indirectly, so no need to declare them in
the source files, just remove the code.

Cc: stable@vger.kernel.org
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: seehearfeel

arch/loongarch/kernel/unwind_orc.c

@@ -350,8 +350,6 @@ EXPORT_SYMBOL_GPL(unwind_start);
 
 static inline unsigned long bt_address(unsigned long ra)
 {
-	extern unsigned long eentry;
-
 #if defined(CONFIG_NUMA) && !defined(CONFIG_PREEMPT_RT)
 	int cpu;
 	int vec_sz = sizeof(exception_handlers);

arch/loongarch/kernel/unwind_prologue.c

@@ -23,10 +23,6 @@ extern const int unwind_hint_lasx;
 extern const int unwind_hint_lbt;
 extern const int unwind_hint_ri;
 extern const int unwind_hint_watch;
-extern unsigned long eentry;
-#ifdef CONFIG_NUMA
-extern unsigned long pcpu_handlers[NR_CPUS];
-#endif
 
 static inline bool scan_handlers(unsigned long entry_offset)
 {

arch/loongarch/mm/tlb.c

@@ -262,7 +262,6 @@ static void output_pgtable_bits_defines(void)
 #ifdef CONFIG_NUMA
 unsigned long pcpu_handlers[NR_CPUS];
 #endif
-extern long exception_handlers[VECSIZE * 128 / sizeof(long)];
 
 static void setup_tlb_handler(int cpu)
 {