[openwrt/openwrt] realtek: update platform support for 5.15

[LEDE Commits]

svanheule pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/1f153558a30a067d83178442e87bca4b67bd120d

commit 1f153558a30a067d83178442e87bca4b67bd120d
Author: INAGAKI Hiroshi <musashino.open at gmail.com>
AuthorDate: Wed Dec 1 12:25:54 2021 +0900

    realtek: update platform support for 5.15
    
    - fw_passed_dtb and others were replaced to get_fdt() function[1]
    - __appended_dtb defined by asm/bootinfo.h[2]
    
    [1]: https://www.spinics.net/lists/linux-mips/msg03332.html
    [2]: https://www.spinics.net/lists/linux-mips/msg03332.html
    
    Signed-off-by: INAGAKI Hiroshi <musashino.open at gmail.com>
---
 target/linux/realtek/files-5.15/arch/mips/rtl838x/prom.c  | 1 -
 target/linux/realtek/files-5.15/arch/mips/rtl838x/setup.c | 7 ++-----
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/target/linux/realtek/files-5.15/arch/mips/rtl838x/prom.c b/target/linux/realtek/files-5.15/arch/mips/rtl838x/prom.c
index dd1b2b170d..abf594aa04 100644
--- a/target/linux/realtek/files-5.15/arch/mips/rtl838x/prom.c
+++ b/target/linux/realtek/files-5.15/arch/mips/rtl838x/prom.c
@@ -25,7 +25,6 @@
 #include <mach-rtl83xx.h>
 
 extern char arcs_cmdline[];
-extern const char __appended_dtb;
 
 struct rtl83xx_soc_info soc_info;
 const void *fdt;
diff --git a/target/linux/realtek/files-5.15/arch/mips/rtl838x/setup.c b/target/linux/realtek/files-5.15/arch/mips/rtl838x/setup.c
index b4d415ab44..546b2fa2f8 100644
--- a/target/linux/realtek/files-5.15/arch/mips/rtl838x/setup.c
+++ b/target/linux/realtek/files-5.15/arch/mips/rtl838x/setup.c
@@ -35,11 +35,8 @@ void __init plat_mem_setup(void)
 
 	set_io_port_base(KSEG1);
 
-	if (fw_passed_dtb) /* UHI interface */
-		dtb = (void *)fw_passed_dtb;
-	else if (&__dtb_start[0] != &__dtb_end[0])
-		dtb = (void *)__dtb_start;
-	else
+	dtb = get_fdt();
+	if (!dtb)
 		panic("no dtb found");
 
 	/*