Remove initramfs_data.{lzo,lzma,gz,bz2}.S variants and use a common
implementation in initramfs_data.S.  The common implementation expects the
file name of the initramfs to be defined in INITRAMFS_IMAGE.

Change the Makefile to set the INITRAMFS_IMAGE define symbol according
to the selected compression method.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: NMichal Marek <mmarek@suse.cz>
Acked-by: N"H. Peter Anvin" <hpa@zytor.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NMichal Marek <mmarek@suse.cz>