LoongArch: Fix kdump failure on v40 interface specification

LoongArch inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I736HO



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

The old memory should be reserved after efi_runtime_init() to avoid destroying
the EFI space and causing failure when executing svam().

Fix the following problems when executing kdump:

[    0.000000] The BIOS Version: Loongson-UDK2018-V2.0.04082-beta7
[    0.000000] CPU 0 Unable to handle kernel paging request at virtual address 00000000fdeb0e7c, era == 00000000fdeb0e7c, ra == 90000000dae6585c
[    0.000000] Oops[#1]:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.10.137+ #86
[    0.000000] Hardware name: Loongson Loongson-3A5000-7A1000-1w-A2101/Loongson-LS3A5000-7A1000-1w-A2101, BIOS vUDK2018-LoongArch-V2.0.pre-beta8 06/15/2022
[    0.000000] $ 0   : 0000000000000000 90000000dae6585c 90000000db200000 90000000db203840
[    0.000000] $ 4   : 0000000000000078 0000000000000028 0000000000000001 00000000db203860
[    0.000000] $ 8   : 0000000000000000 0000000000000040 90000000db203680 0000000000000000
[    0.000000] $12   : 00000000fdeb0e7c ffffffffffffffc0 00000000fbffffff 0000000020000000
[    0.000000] $16   : 000000000003e780 0000000020000000 90000000dad8c348 0000000000003fff
[    0.000000] $20   : 0000000000000018 90000000dad8bdd0 90000000db203850 0000000000000040
[    0.000000] $24   : 000000000000000f 90000000db21a570 90000000daeb07a0 90000000db217000
[    0.000000] $28   : 90000000db203858 0000000001ffffff 90000000db2171b0 0000000000000040
[    0.000000] era   : 00000000fdeb0e7c 0xfdeb0e7c
[    0.000000] ra    : 90000000dae6585c set_virtual_map.isra.0+0x23c/0x394
[    0.000000] CSR crmd: 90000000db21a570
[    0.000000] CSR prmd: 00000000
[    0.000000] CSR euen: 00000000
[    0.000000] CSR ecfg: 90000000db203850
[    0.000000] CSR estat: 90000000dae65800
[    0.000000] ExcCode : 26 (SubCode 16b)
[    0.000000] PrId  : 0014c012 (Loongson-64bit)
[    0.000000] Modules linked in:
[    0.000000] Process swapper (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____))
[    0.000000] Stack : 0000000000000001 00000000fdeb0e7c 0000000000036780 000000000003e780
[    0.000000]         0000000000000006 0000000010000000 8000000010000000 0000000000010000
[    0.000000]         8000000000000001 0000000000000005 00000000fde40000 90000000fde40000
[    0.000000]         0000000000000100 800000000000000f 0000000000000006 00000000fdf40000
[    0.000000]         90000000fdf40000 0000000000000300 800000000000000f 00000000000000b0
[    0.000000]         0000000000000001 90000000da094cf0 0000000000000000 ffffffffffffffea
[    0.000000]         90000000db2039b8 ffff0a1000000609 0000000000000035 0000000000000030
[    0.000000]         90000000dad7b258 0000000000000400 00000000000000b0 ffff0a1000000609
[    0.000000]         90000000db2039a8 90000000db095730 000000007fffffff ffff0a1000000609
[    0.000000]         90000000db203a90 90000000db203a30 90000000db2039d8 90000000db09570b
[    0.000000]         ...
[    0.000000] Call Trace:
[    0.000000]
[    0.000000] Code: (Bad address in era)
[    0.000000]
[    0.000000]

Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Change-Id: I1cdf06f520fd16fa2c2dcc6b852d76d038771a86