LoongArch: Use unsigned long for _end and _text

It is better to use unsigned long rather than long for _end and _text to
calculate the kernel length.

Cc: stable@vger.kernel.org # v6.3+
Fixes: e5f02b5 ("LoongArch: Add support for kernel address space layout randomization (KASLR)")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: seehearfeel

arch/loongarch/kernel/relocate.c

@@ -183,7 +183,7 @@ static inline void __init *determine_relocation_address(void)
 	if (kaslr_disabled())
 		return destination;
 
-	kernel_length = (long)_end - (long)_text;
+	kernel_length = (unsigned long)_end - (unsigned long)_text;
 
 	random_offset = get_random_boot() << 16;
 	random_offset &= (CONFIG_RANDOMIZE_BASE_MAX_OFFSET - 1);
@@ -232,7 +232,7 @@ unsigned long __init relocate_kernel(void)
 	early_memunmap(cmdline, COMMAND_LINE_SIZE);
 
 	if (random_offset) {
-		kernel_length = (long)(_end) - (long)(_text);
+		kernel_length = (unsigned long)(_end) - (unsigned long)(_text);
 
 		/* Copy the kernel to it's new location */
 		memcpy(location_new, _text, kernel_length);