LoongArch: Fix section mismatch due to acpi_os_ioremap()

mainline inclusion
from mainline-v6.0-rc4
commit e0fba87c
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6BWFP


CVE: NA

--------------------------------

Now acpi_os_ioremap() is marked with __init because it calls memblock_
is_memory() which is also marked with __init in the !ARCH_KEEP_MEMBLOCK
case. However, acpi_os_ioremap() is called by ordinary functions such
as acpi_os_{read, write}_memory() and causes section mismatch warnings:

WARNING: modpost: vmlinux.o: section mismatch in reference: acpi_os_read_memory (section: .text) -> acpi_os_ioremap (section: .init.text)
WARNING: modpost: vmlinux.o: section mismatch in reference: acpi_os_write_memory (section: .text) -> acpi_os_ioremap (section: .init.text)

Fix these warnings by selecting ARCH_KEEP_MEMBLOCK unconditionally and
removing the __init modifier of acpi_os_ioremap(). This can also give a
chance to track "memory" and "reserved" memblocks after early boot.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Change-Id: If0cd1baeb01c8d627c70c2f1b4569d6ac68bf696
(cherry picked from commit f3b12c25)