Reduce OneNAND IPL common code

Reduce OneNAND IPL common code

OneNAND IPL has common codes for RAM init, load data, and jump to 2nd
bootloader, but it's common code used about 300~400 bytes. So board
specific codes, such as lowlevel_init, can't has enough code. It make
a difficult to implement OneNAND IPL.

his patch make this common code as small as possible. and give
lowlevel_init can have more codes.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>