ARM: 7737/1: fix kernel decompressor compilation error with CONFIG_DEBUG_SEMIHOSTING

Selecting this option produces:

  AS      arch/arm/boot/compressed/debug.o
arch/arm/boot/compressed/debug.S:4:33: fatal error: mach/debug-macro.S: No such file or directory
compilation terminated.
make[3]: *** [arch/arm/boot/compressed/debug.o] Error 1

The semihosting support cannot be modelled into a senduart macro as
it requires memory space for argument passing.  So the
CONFIG_DEBUG_LL_INCLUDE may not have any sensible value and the include
directive should be omitted.

While at it, let's add proper semihosting output support to the
decompressor.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>