[ARM] 3547/1: PXA-OHCI: Allow platforms to specify a power budget

Patch from Richard Purdie

Add a power budget variable to the PXA OHCI platform data and add a
default value for the spitz platform(s) which prevents known failures
with certain USB devices.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>