ARM: 7671/1: use Kconfig to select uncompress.h

Following the approach handling DEBUG_LL inclusion, the patch creates
a Kconfig symbol CONFIG_UNCOMPRESS_INCLUDE for choosing the correct
uncompress header.  For traditional build, mach/uncompress.h will be
included in arch/arm/boot/compressed/misc.c.  For multiplatform build,
debug/uncompress.h which contains a suite of empty functions will be
used.  In this way, a platform with particular uncompress.h
implementation could choose its own uncompress.h with this Kconfig
option.

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