treewide: Use conventional names for 32-bit and 64-bit

There are several places in the source tree that have:

  32bit, 32 bit, 64bit, 64 bit

Fix by using the conventional names with a hyphen.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Acked-by: Anup Patel <anup.patel@wdc.com>