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 <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/19433
Signed-off-by: Hauke Mehrtens <[email protected]>

target/linux/ramips/image/mt7621.mk

@@ -2824,8 +2824,8 @@ define Device/tplink_eap615-wall-v1
   DEVICE_VARIANT := v1
   DEVICE_PACKAGES := kmod-mt7915-firmware -uboot-envtools
   TPLINK_BOARD_ID := EAP615-WALL-V1
-  KERNEL := kernel-bin | lzma | fit lzma $$(KDIR)/image-$$(firstword $$(DEVICE_DTS)).dtb | pad-to 64k
-  KERNEL_INITRAMFS := kernel-bin | lzma | fit lzma $$(KDIR)/image-$$(firstword $$(DEVICE_DTS)).dtb with-initrd
+  KERNEL := kernel-bin | lzma -d22 | fit lzma $$(KDIR)/image-$$(firstword $$(DEVICE_DTS)).dtb | pad-to 64k
+  KERNEL_INITRAMFS := kernel-bin | lzma -d22 | fit lzma $$(KDIR)/image-$$(firstword $$(DEVICE_DTS)).dtb with-initrd
   IMAGE_SIZE := 13248k
 endef
 TARGET_DEVICES += tplink_eap615-wall-v1