OMAP: remove unused parameter arch_id from uncompress.h

There is not point in having arch_id as parameter of __arch_decomp_setup(),
nothing in it uses arch_id. The machine id is already exported (and used)
with symbol __machine_arch_type as per mach-types.h.

Removing the pointless macro as well.

Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>