Initramfs initrd images do not need a ramdisk device, so remove this
restriction in Kconfig. BLK_DEV_RAM=n saves about 13k on i386. Also
without ramdisk device there's no need for "dry run", so initramfs unpacks
much faster.
People using cramfs, squashfs, or gzipped ext2/minix initrd images are
probably smart enough not to turn off ramdisk support by accident.
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>