aclocal.m4: remove dnl which made autoconf complain
aclocal.m4: remove dnl which made autoconf complain

autoconf complained about this dnl, and it's not necessary anyway (and
perhaps even potentially harmful?

Signed-off-by: H. Peter Anvin <8a453bad9912ffe59bc0f0b8abe03df9be19379e@linux.intel.com>

techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm