LoongArch: Remove the .fixup section usage

mainline inclusion
from mainline-v6.2-rc1
commit 912bcfaf
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6BWFP


CVE: NA

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Use the `.L_xxx` label to improve fixup code and then remove the .fixup
section usage.

Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Change-Id: I01c14c9bbc99baffe611d7e27f4c87d494b73026