Remove the miniroot for the OMAP3 BeagleBoards. Ethernet is on USB and

USB isn't supported.  The installer turns out to have been broken on
BeagleBoard for over a year and no one noticed.  The existing support
for OMAP3 in the kernel remains though it isn't clear if anyone has
tried it after the fdt changes went in.
ok patrick@ tom@ kettenis@ matthieu@

src/etc/etc.armv7/Makefile.inc

@@ -1,10 +1,10 @@
-#	$OpenBSD: Makefile.inc,v 1.15 2017/04/04 00:03:12 deraadt Exp $
+#	$OpenBSD: Makefile.inc,v 1.16 2017/09/01 04:40:40 jsg Exp $
 
 bootblocks:
 	cp -p ${DESTDIR}/usr/mdec/BOOTARM.EFI ${RELEASEDIR}
 
 MDEXT=	bsd.rd BOOTARM.EFI \
-	miniroot-am335x-${OSrev}.fs miniroot-beagle-${OSrev}.fs \
+	miniroot-am335x-${OSrev}.fs \
 	miniroot-cubie-${OSrev}.fs miniroot-cubox-${OSrev}.fs \
 	miniroot-nitrogen-${OSrev}.fs miniroot-panda-${OSrev}.fs \
 	miniroot-wandboard-${OSrev}.fs