nasm: Move rootfile to the x86_64 subdirectory

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

diff --git a/config/rootfiles/common/nasm b/config/rootfiles/common/x86_64/nasm
similarity index 100%
rename from config/rootfiles/common/nasm
rename to config/rootfiles/common/x86_64/nasm