mach-integrator: fix VGA base regression

mach-integrator: fix VGA base regression

The changes introduced in commit
b55451d873c65b32b5a708ca8c3dee18a7764217
"ARM: set vga memory base at run-time"

Makes the Integrator/AP freeze completely. I appears that
this is due to the VGA base address being assigned at PCI
init time, while this base is needed earlier than that.
Moving the initialization of the base address to the
.map_io function solves this problem.

Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>