ARM: at91: add explicit include of hardware.h to uncompressor

In preparation to remove mach/io.h, add explicit include of hardware.h.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Andrew Victor <linux@maxim.org.za>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>