rc: allow to disable trim for the brave

Requires fiddling with /etc/fstab, at least that is a file
that we never touch.  It's harder for installs that need
TRIM to be off all the time as the first boot does actually
enable it.  That means after the install is complete it needs
to be CTRL+C'ed and the fstab entry modified before reboot.

PR: https://forum.opnsense.org/index.php?topic=3044

src/etc/rc

@@ -35,7 +35,13 @@ while read FS_PART FS_MNT FS_TYPE FS_MORE; do
 	FS_DEV=$(echo ${FS_PART} | awk 'match($0, /\/dev\/([a-z]+[0-9]+)/) { print substr( $0, RSTART, RLENGTH )}')
 	FS_TRIM=$(camcontrol identify ${FS_DEV} | grep TRIM | awk '{ print $5; }')
 	if [ "${FS_TRIM}" = "yes" ]; then
-		tunefs -t enable ${FS_MNT}
+		# appending "# notrim" to the /etc/fstab entry
+		# will allow to strip trim and leave it disabled
+		if echo "${FS_MORE}" | grep -iq notrim; then
+			tunefs -t disable ${FS_MNT}
+		else
+			tunefs -t enable ${FS_MNT}
+		fi
 	fi
 done < /etc/fstab