[openwrt/openwrt] realtek: switch Zyxel GS1900 initramfs recipe to rt-loader

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/8eea85584633d6cf70c8a043629e09b1781d90f5

commit 8eea85584633d6cf70c8a043629e09b1781d90f5
Author: Markus Stockhausen <markus.stockhausen at gmx.de>
AuthorDate: Wed Aug 6 01:54:29 2025 -0400

    realtek: switch Zyxel GS1900 initramfs recipe to rt-loader
    
    These devices need a tiny (<8MB) initramfs. There are first
    occurrences where this fails with newer kernels and diagnostic
    packages.
    
    Switch the recipe over to use lzma compression and rt-loader.
    
    Signed-off-by: Markus Stockhausen <markus.stockhausen at gmx.de>
    Link: https://github.com/openwrt/openwrt/pull/19687
    Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 target/linux/realtek/image/common.mk | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/target/linux/realtek/image/common.mk b/target/linux/realtek/image/common.mk
index d68915ea90..39c97cd845 100644
--- a/target/linux/realtek/image/common.mk
+++ b/target/linux/realtek/image/common.mk
@@ -86,8 +86,9 @@ define Device/zyxel_gs1900
   KERNEL_INITRAMFS := \
 	kernel-bin | \
 	append-dtb | \
-	libdeflate-gzip | \
+	rt-compress | \
 	zyxel-vers | \
-	uImage gzip | \
+	rt-loader | \
+	uImage none | \
 	check-size 6976k
 endef