ramips: EAP615-Wall v1: fix bootloop by reducing LZMA dictionary

ramips: EAP615-Wall v1: fix bootloop by reducing LZMA dictionary

Fix bootloop on TP-Link EAP615-Wall v1 by reducing LZMA dictionary
size. Before this patch and after an upgrade to kernel 6.12 this
device couldn't boot a kernel because of an error: "lzma compressed:
uncompress error 1".

I have chosen -d22 as dictionary size as suggested by @namiltd.
The usual sizes for problematic devices are -d16, -d20, -d22. I
have confirmed with my tests that this device can boot with a value
up to -d27, but there is no size benefit from values above -d21,
therefore -d22 is good enough.

See also: https://github.com/openwrt/openwrt/issues/19403

Signed-off-by: Marcin FM <marcin@ipv8.pl>
Link: https://github.com/openwrt/openwrt/pull/19433
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>