ramips: fix initramfs kernel loadaddr for EAP615-Wall v1

ramips: fix initramfs kernel loadaddr for EAP615-Wall v1

The kernel load address was changed in commit e2d823d06830 ("ramips:
fix LZMA decompression error for TP-Link EAP615-Wall"). We also need
to relocate the load address for initramfs image so that it can be
booted correctly.

Fixes: e2d823d06830 ("ramips: fix LZMA decompression error for TP-Link EAP615-Wall")
Fixes: https://github.com/openwrt/openwrt/issues/22505
Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
Link: https://github.com/openwrt/openwrt/pull/22562
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>