Documentation: Fix Broken URL "freshmeat"

Fix broken URL in documents "freshmeat" to "freecode" in
Documentation/filesystems/ramfs-rootfs-initramfs.txt,
Documentation/scsi/scsi-generic.txt
Documentation/usb/mtouchusb.txt

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>