Revert "LoongArch: BPF: Fix off-by-one error in build_prologue()"

This reverts commit e9ccb262 which is
commit 7e258699 upstream.

It breaks the build.

Link: https://lore.kernel.org/r/90288944-3f5b-45b7-ae7d-c7a54398db55@roeck-us.neta


Reported-by: Guenter Roeck <linux@roeck-us.net>
Cc: Vincent Li <vincent.mc.li@gmail.com>
Cc: Hengqi Chen <hengqi.chen@gmail.com>
Cc: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>