[ARM] 4564/1: Add tagged list support for Acorn RiscPC's uncompress code

arch_decomp_setup() does not understand the new tagged lists
for parameter setup. It's fixed in using the older param struct.

This patch adds support for tagged lists and allows the older
param struct too.

Signed-off-by: Alan Hourihane <alanh@fairlite.demon.co.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>