make major numbers match bdevsw[]

used by config(8) for non-generic kernels with specific
root/dump/swap devices

Index: sys/arch/arm64/conf/files.arm64
===================================================================
RCS file: /cvs/src/sys/arch/arm64/conf/files.arm64,v
diff -u -p -r1.70 files.arm64
--- sys/arch/arm64/conf/files.arm64	2 Jul 2024 10:25:16 -0000	1.70
+++ sys/arch/arm64/conf/files.arm64	4 Nov 2024 02:04:15 -0000
@@ -3,9 +3,9 @@
 maxpartitions	16
 maxusers	2 8 128
 
-major	{wd = 16}
-major	{sd = 24}
-major	{cd = 26}
+major	{wd = 0}
+major	{sd = 4}
+major	{cd = 6}
 major	{rd = 17}
 
 file	arch/arm64/arm64/autoconf.c