Remove NAND and NANDFS support

NANDFS has been broken for years. Remove it. The NAND drivers that
remain are for ancient parts that are no longer relevant. They are
polled, have terrible performance and just for ancient arm
hardware. NAND parts have evolved significantly from this early work
and little to none of it would be relevant should someone need to
update to support raw nand. This code has been off by default for
years and has violated the vnode protocol leading to panics since it
was committed.

Numerous posts to arch@ and other locations have found no actual users
for this software.

Relnotes:	Yes
No Objection From: arch@
Differential Revision: https://reviews.freebsd.org/D20745

include/Makefile

@@ -48,7 +48,7 @@ LSUBDIRS=	cam/ata cam/mmc cam/nvme cam/scsi \
 	dev/ic dev/iicbus dev/io dev/mfi dev/mmc dev/nvme \
 	dev/ofw dev/pbio dev/pci ${_dev_powermac_nvram} dev/ppbus dev/pwm \
 	dev/smbus dev/speaker dev/tcp_log dev/veriexec dev/vkbd dev/wi \
-	fs/devfs fs/fdescfs fs/msdosfs fs/nandfs fs/nfs fs/nullfs \
+	fs/devfs fs/fdescfs fs/msdosfs fs/nfs fs/nullfs \
 	fs/procfs fs/smbfs fs/udf fs/unionfs \
 	geom/cache geom/concat geom/eli geom/gate geom/journal geom/label \
 	geom/mirror geom/mountver geom/multipath geom/nop \
@@ -158,7 +158,7 @@ copies: .PHONY .META
 		done; \
 	fi
 .endfor
-.for i in ${LDIRS} ${LSUBDIRS:Ndev/agp:Ndev/acpica:Ndev/bktr:Ndev/evdev:Ndev/hyperv:Ndev/nand:Ndev/pci:Ndev/veriexec} ${LSUBSUBDIRS}
+.for i in ${LDIRS} ${LSUBDIRS:Ndev/agp:Ndev/acpica:Ndev/bktr:Ndev/evdev:Ndev/hyperv:Ndev/pci:Ndev/veriexec} ${LSUBSUBDIRS}
 	cd ${SRCTOP}/sys; \
 	${INSTALL} -C ${TAG_ARGS} -o ${BINOWN} -g ${BINGRP} -m 444 $i/*.h \
 	    ${SDESTDIR}${INCLUDEDIR}/$i
@@ -174,13 +174,6 @@ copies: .PHONY .META
 	cd ${SRCTOP}/sys/dev/bktr; \
 	${INSTALL} -C ${TAG_ARGS} -o ${BINOWN} -g ${BINGRP} -m 444 ioctl_*.h \
 	    ${SDESTDIR}${INCLUDEDIR}/dev/bktr
-.if ${MK_NAND} != "no"
-	cd ${SRCTOP}/sys/dev/nand; \
-	${INSTALL} -C ${TAG_ARGS} -o ${BINOWN} -g ${BINGRP} -m 444 nandsim.h \
-	    ${SDESTDIR}${INCLUDEDIR}/dev/nand; \
-	${INSTALL} -C ${TAG_ARGS} -o ${BINOWN} -g ${BINGRP} -m 444 nand_dev.h \
-	    ${SDESTDIR}${INCLUDEDIR}/dev/nand
-.endif
 	cd ${SRCTOP}/sys/dev/evdev; \
 	${INSTALL} -C -o ${BINOWN} -g ${BINGRP} -m 444 input.h \
 	    ${SDESTDIR}${INCLUDEDIR}/dev/evdev; \
@@ -268,7 +261,7 @@ symlinks: .PHONY .META
 		${INSTALL_SYMLINK} ${TAG_ARGS} ../../../sys/$i/$$h ${SDESTDIR}${INCLUDEDIR}/$i; \
 	done
 .endfor
-.for i in ${LSUBDIRS:Ndev/agp:Ndev/acpica:Ndev/bktr:Ndev/evdev:Ndev/hyperv:Ndev/nand:Ndev/pci:Ndev/veriexec}
+.for i in ${LSUBDIRS:Ndev/agp:Ndev/acpica:Ndev/bktr:Ndev/evdev:Ndev/hyperv:Ndev/pci:Ndev/veriexec}
 	cd ${SRCTOP}/sys/$i; \
 	for h in *.h; do \
 		${INSTALL_SYMLINK} ${TAG_ARGS} ../../../../sys/$i/$$h ${SDESTDIR}${INCLUDEDIR}/$i; \
@@ -289,13 +282,6 @@ symlinks: .PHONY .META
 		${INSTALL_SYMLINK} ${TAG_ARGS} ../../../../sys/dev/bktr/$$h \
 		    ${SDESTDIR}${INCLUDEDIR}/dev/bktr; \
 	done
-.if ${MK_NAND} != "no"
-	cd ${SRCTOP}/sys/dev/nand; \
-	for h in nandsim.h nand_dev.h; do \
-		${INSTALL_SYMLINK} ${TAG_ARGS} ../../../../sys/dev/nand/$$h \
-		    ${SDESTDIR}${INCLUDEDIR}/dev/nand; \
-	done
-.endif
 	cd ${SRCTOP}/sys/dev/evdev; \
 	for h in input.h input-event-codes.h uinput.h; do \
 		ln -fs ../../../../sys/dev/evdev/$$h \