riscv: kasan: Fix MODULES_VADDR evaluation due to local variables' name

commit 2bfc6cd8 ("riscv: Move kernel mapping outside of linear
mapping") makes use of MODULES_VADDR to populate kernel, BPF, modules
mapping. Currently, MODULES_VADDR is defined as below for RV64:

| #define MODULES_VADDR   (PFN_ALIGN((unsigned long)&_end) - SZ_2G)

But kasan_init() has two local variables which are also named as _start,
_end, so MODULES_VADDR is evaluated with the local variable _end
rather than the global "_end" as we expected. Fix this issue by
renaming the two local variables.

Fixes: 2bfc6cd8 ("riscv: Move kernel mapping outside of linear mapping")
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

arch/riscv/mm/kasan_init.c

@@ -169,7 +169,7 @@ static void __init kasan_shallow_populate(void *start, void *end)
 
 void __init kasan_init(void)
 {
-	phys_addr_t _start, _end;
+	phys_addr_t p_start, p_end;
 	u64 i;
 
 	/*
@@ -189,9 +189,9 @@ void __init kasan_init(void)
 			(void *)kasan_mem_to_shadow((void *)VMALLOC_END));
 
 	/* Populate the linear mapping */
-	for_each_mem_range(i, &_start, &_end) {
-		void *start = (void *)__va(_start);
-		void *end = (void *)__va(_end);
+	for_each_mem_range(i, &p_start, &p_end) {
+		void *start = (void *)__va(p_start);
+		void *end = (void *)__va(p_end);
 
 		if (start >= end)
 			break;