ARM: 6663/1: make Thumb2 kernel entry point more similar to the ARM one

Some installers would binary patch the kernel zImage to replace the
first few nops with custom instructions.  This breaks the Thumb2 kernel
as the mode switch is right at the beginning.  Let's move it towards the
end of the nop sequence instead.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>