[ARM] 3662/1: ixp23xx: don't include asm/hardware.h in uncompress.h

Patch from Lennert Buytenhek

ixp23xx was including asm/hardware.h in its version of uncompress.h,
to get at the physical address of the debug UART, but this include was
causing various inline functions that are totally unrelated to the
decompressor, defined in headers in include/asm-arm/arch-ixp23xx, to
be included in the decompressor image.

Include asm/arch/ixp23xx.h instead, and move the sole inline function
in ixp23xx.h to another header.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>