tools: kwboot: Replace ARM mov + movt instruction pair by mov + orr

Older Armada SoCs have custom ARMv5te compatible core which does not
support movt instruction. So replace mov + movt instruction pair used for
immediate move construction by mov + orr instructions which are supported
also by ARMv5te.

After this change kwboot ARM code should be compatible with any 32-bit ARM
core compatible by ARMv2 or new. At least GNU AS does not throw any error
or warning.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>