[contrib][linux] Disable ASM in the kernel

Disable ASM in the kernel for now. It requires a few changes & setup to
get working. Instead of doing it in a zstd version update, I'd prefer to
package that change as a single patch, and propose it separately from
the version update. This makes the version update easier, and reduces
some risk.

contrib/linux-kernel/linux.mk

@@ -29,7 +29,6 @@ zstd_compress-y := \
 
 zstd_decompress-y := \
 		zstd_decompress_module.o \
-		decompress/huf_decompress_amd64.o \
 		decompress/huf_decompress.o \
 		decompress/zstd_ddict.o \
 		decompress/zstd_decompress.o \