mtd/nand/ubi: assortment of alignment fixes

Various U-Boot adoptions/extensions to MTD/NAND/UBI did not take buffer
alignment into account which led to failures of the following form:

ERROR: v7_dcache_inval_range - start address is not aligned - 0x1f7f0108
ERROR: v7_dcache_inval_range - stop address is not aligned - 0x1f7f1108

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Scott Wood <scottwood@freescale.com>
[trini: Add __UBOOT__ hunk to lib/zlib/zutil.c due to malloc.h in common.h]
Signed-off-by: Tom Rini <trini@konsulko.com>