[kernel compile]RAM disk support for RH/fedora distro

Make sure enable RAM disk support and have enough space for kernel image aslo, have loopback device enable(CONFIG_BLK_DEV_LOOP=y).
Otherwise,it will complain about "all of the loopback devices
are in use", mkinitrd failed.

enable ssh and other service

Method 1.
1. run setup on RH
2. chkconfig --level 345 sshd on